Drinking Water Quality

The federal Centers for Disease Control and Prevention (CDC) tracks information about the environment and human health, and DHEC’s Bureau of Water is tracking arsenic, nitrate, and disinfection byproducts in public drinking water as part of the CDC’s National Environmental Public Health Tracking Program.

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Drinking Water Quality Data

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Number of Community Water Systems and Total Population Served (1999-2010)

Number of Community Water Systems and Total Population Served
Year	Number of CWS1	Total Population Served
1999	588	3,304,040
2000	589	3,305,246
2001	590	3,305,781
2002	595	3,342,016
2003	599	3,336,995
2004	603	3,381,910
2005	606	3,467,468
2006	607	3,470,798
2007	608	3,595,395
2008	608	3,657,580
2009	608	3,820,599
2010	603	3,860,095
1 Community Water System (CWS)   A Community Water System or CWS is defined by the EPA as a public water system that supplies water to the same population year-round.  A public water system is defined as one that provides water for human consumption through a pipe or other constructed conduit to at least fifteen (15) service connectors or serves an average of at least twenty-five (25) people for at least sixty (60) days a year. Data Source: Bureau of Water

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Arsenic Data

Number of Community Water Systems (CWS) and Population Served by Mean Arsenic Concentrations (micrograms per liter), by Year (1999-2002) (2003-2006) (2007-2010)

Number of Community Water Systems1 (CWS) and Population Served by Mean Arsenic Concentrations (micrograms per liter), by Year (1999-2002)
	1999		2000		2001		2002
Concentration in µg/L	Number of CWS	Population Served	Number of CWS	Population Served	Number of CWS	Population Served	Number of CWS	Population Served
Not Sampled	588	3,304,040	589	3,305,246	586	3,305,383	436	2,357,770
<5	0	0	0	0	0	0	2	60,221
5 - <10	0	0	0	0	4	398	156	923,833
10 - <202	0	0	0	0	0	0	1	192
20 - <302	0	0	0	0	0	0	0	0
30+2	0	0	0	0	0	0	0	0
1 Community Water System (CWS)   A Community Water System or CWS is defined by the EPA as a public water system that supplies water to the same population year-round.  A public water system is defined as one that provides water for human consumption through a pipe or other constructed conduit to at least fifteen (15) service connectors or serves an average of at least twenty-five (25) people for at least sixty (60) days a year. 2 Maximum Contaminant Level (MCL)  Limits set by the EPA for the presence of contaminants in drinking water; an MCL is the highest amount of a substance allowed under the Clean Water Act. The MCL for Arsenic is 10µg/L. Data Source: Bureau of Water

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Number of Community Water Systems1 (CWS) and Population Served by Mean Arsenic Concentrations (micrograms per liter), by Year (2003-2006)
	2003		2004		2005		2006
Concentration in µg/L	Number of CWS	Population Served	Number of CWS	Population Served	Number of CWS	Population Served	Number of CWS	Population Served
Not Sampled	393	1,199,563	348	1,021,978	374	1,329,850	432	1,381,489
<5	46	930,281	139	1,235,454	229	2,136,496	173	2,088,559
5 - <10	159	1,206,959	115	1,124,286	3	1,122	2	750
10 - <202	1	192	1	192	0	0	0	0
20 - <302	0	0	0	0	0	0	0	0
30+2	0	0	0	0	0	0	0	0
1 Community Water System (CWS)   A Community Water System or CWS is defined by the EPA as a public water system that supplies water to the same population year-round.  A public water system is defined as one that provides water for human consumption through a pipe or other constructed conduit to at least fifteen (15) service connectors or serves an average of at least twenty-five (25) people for at least sixty (60) days a year. 2 Maximum Contaminant Level (MCL)  Limits set by the EPA for the presence of contaminants in drinking water; an MCL is the highest amount of a substance allowed under the Clean Water Act. The MCL for Arsenic is 10µg/L. Data Source: Bureau of Water

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Number of Community Water Systems1 (CWS) and Population Served by Mean Arsenic Concentrations (micrograms per liter), by Year (2007 - 2010)
	2007		2008		2009		2010
Concentration in µg/L	Number of CWS	Population Served	Number of CWS	Population Served	Number of CWS	Population Served	Number of CWS	Population Served
Not Sampled	464	2,000,105	415	1,370,627	413	1,575,318	397	1,505,727
<5	142	1,594,196	191	2,285,555	192	2,244,679	205	2,353,876
5 - <10	1	1,045	1	906	2	110	0	0
10 - <202	1	49	1	492	1	492	1	492
20 - <302	0	0	0	0	0	0	0	0
30+2	0	0	0	0	0	0	0	0
1 Community Water System (CWS)   A Community Water System or CWS is defined by the EPA as a public water system that supplies water to the same population year-round.  A public water system is defined as one that provides water for human consumption through a pipe or other constructed conduit to at least fifteen (15) service connectors or serves an average of at least twenty-five (25) people for at least sixty (60) days a year. 2 Maximum Contaminant Level (MCL)  Limits set by the EPA for the presence of contaminants in drinking water; an MCL is the highest amount of a substance allowed under the Clean Water Act. The MCL for Arsenic is 10µg/L. Data Source: Bureau of Water

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Number of Community Water Systems (CWS) and Population Served by Max Arsenic Concentrations (micrograms per liter), by Year (1999-2002) (2003-2006) (2007-2010)

Number of Community Water Systems1 (CWS) and Population Served by Max Arsenic Concentrations (micrograms per liter), by Year (1999-2002)
	1999		2000		2001		2002
Concentration in µg/L	Number of CWS	Population Served	Number of CWS	Population Served	Number of CWS	Population Served	Number of CWS	Population Served
Not Sampled	588	3,304,040	589	3,305,246	586	3,305,383	436	2,357,770
<5	0	0	0	0	0	0	1	5,912
5 - <10	0	0	0	0	4	398	156	969,341
10 - <202	0	0	0	0	0	0	1	192
20 - <302	0	0	0	0	0	0	1	8,801
30+2	0	0	0	0	0	0	0	0
1 Community Water System (CWS)   A Community Water System or CWS is defined by the EPA as a public water system that supplies water to the same population year-round.  A public water system is defined as one that provides water for human consumption through a pipe or other constructed conduit to at least fifteen (15) service connectors or serves an average of at least twenty-five (25) people for at least sixty (60) days a year. 2 Maximum Contaminant Level (MCL)  Limits set by the EPA for the presence of contaminants in drinking water; an MCL is the highest amount of a substance allowed under the Clean Water Act. The MCL for Arsenic is 10µg/L. Data Source: Bureau of Water

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Number of Community Water Systems1 (CWS) and Population Served by Max Arsenic Concentrations (micrograms per liter), by Year (2003-2006)
	2003		2004		2005		2006
Concentration in µg/L	Number of CWS	Population Served	Number of CWS	Population Served	Number of CWS	Population Served	Number of CWS	Population Served
Not Sampled	393	1,199,563	348	1,021,978	374	1,329,850	432	1,381,489
<5	22	61,142	111	442,994	228	2,127,511	173	2,088,559
5 - <10	182	2,067,297	142	1,893,548	3	1,122	1	258
10 - <202	1	192	1	192	0	0	1	492
20 - <302	1	8,801	1	23,198	1	8,985	0	0
30+2	0	0	0	0	0	0	0	0
1 Community Water System (CWS)   A Community Water System or CWS is defined by the EPA as a public water system that supplies water to the same population year-round.  A public water system is defined as one that provides water for human consumption through a pipe or other constructed conduit to at least fifteen (15) service connectors or serves an average of at least twenty-five (25) people for at least sixty (60) days a year. 2 Maximum Contaminant Level (MCL)  Limits set by the EPA for the presence of contaminants in drinking water; an MCL is the highest amount of a substance allowed under the Clean Water Act. The MCL for Arsenic is 10µg/L. Data Source: Bureau of Water

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Number of Community Water Systems1 (CWS) and Population Served by Max Arsenic Concentrations (micrograms per liter), by Year (2007 - 2010)
	2007		2008		2009		2010
Concentration in µg/L	Number of CWS	Population Served	Number of CWS	Population Served	Number of CWS	Population Served	Number of CWS	Population Served
Not Sampled	464	2,000,105	415	1,370,627	413	1,575,318	397	1,505,727
<5	142	1,594,196	189	2,276,373	190	2,235,386	205	2,353,876
5 - <10	1	1,045	2	955	2	202	0	0
10 - <202	1	49	0	0	2	560	1	492
20 - <302	0	0	2	9,625	1	9,133	0	0
30+2	0	0	0	0	0	0	0	0
1 Community Water System (CWS)   A Community Water System or CWS is defined by the EPA as a public water system that supplies water to the same population year-round.  A public water system is defined as one that provides water for human consumption through a pipe or other constructed conduit to at least fifteen (15) service connectors or serves an average of at least twenty-five (25) people for at least sixty (60) days a year. 2 Maximum Contaminant Level (MCL)  Limits set by the EPA for the presence of contaminants in drinking water; an MCL is the highest amount of a substance allowed under the Clean Water Act. The MCL for Arsenic is 10µg/L. Data Source: Bureau of Water

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Number of Community Water Systems (CWS) and Population Served by Mean Arsenic Concentrations (micrograms per liter), by Quarter (1999) (2000) (2001) (2002) (2003) (2004) (2005) (2006) (2007) (2008) (2009) (2010)

Number of Community Water Systems1 (CWS) and Population Served by Mean Arsenic Concentrations (micrograms per liter), by Quarter (1999)
	1999
	1st Quarter		2nd Quarter		3rd Quarter		4th Quarter
Concentration in µg/L	Number of CWS	Population Served	Number of CWS	Population Served	Number of CWS	Population Served	Number of CWS	Population Served
Not Sampled	588	3,304,040	588	3,304,040	588	3,304,040	588	3,304,040
<5	0	0	0	0	0	0	0	0
5 - <10	0	0	0	0	0	0	0	0
10 - <202	0	0	0	0	0	0	0	0
20 - <302	0	0	0	0	0	0	0	0
30+2	0	0	0	0	0	0	0	0
1 Community Water System (CWS)   A Community Water System or CWS is defined by the EPA as a public water system that supplies water to the same population year-round.  A public water system is defined as one that provides water for human consumption through a pipe or other constructed conduit to at least fifteen (15) service connectors or serves an average of at least twenty-five (25) people for at least sixty (60) days a year. 2 Maximum Contaminant Level (MCL)  Limits set by the EPA for the presence of contaminants in drinking water; an MCL is the highest amount of a substance allowed under the Clean Water Act. The MCL for Arsenic is 10µg/L. Data Source: Bureau of Water

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Number of Community Water Systems1 (CWS) and Population Served by Mean Arsenic Concentrations (micrograms per liter), by Quarter (2000)
	2000
	1st Quarter		2nd Quarter		3rd Quarter		4th Quarter
Concentration in µg/L	Number of CWS	Population Served	Number of CWS	Population Served	Number of CWS	Population Served	Number of CWS	Population Served
Not Sampled	589	3,305,246	589	3,305,246	589	3,305,246	589	3,305,246
<5	0	0	0	0	0	0	0	0
5 - <10	0	0	0	0	0	0	0	0
10 - <202	0	0	0	0	0	0	0	0
20 - <302	0	0	0	0	0	0	0	0
30+2	0	0	0	0	0	0	0	0
1 Community Water System (CWS)   A Community Water System or CWS is defined by the EPA as a public water system that supplies water to the same population year-round.  A public water system is defined as one that provides water for human consumption through a pipe or other constructed conduit to at least fifteen (15) service connectors or serves an average of at least twenty-five (25) people for at least sixty (60) days a year. 2 Maximum Contaminant Level (MCL)  Limits set by the EPA for the presence of contaminants in drinking water; an MCL is the highest amount of a substance allowed under the Clean Water Act. The MCL for Arsenic is 10µg/L. Data Source: Bureau of Water

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Number of Community Water Systems1 (CWS) and Population Served by Mean Arsenic Concentrations (micrograms per liter), by Quarter (2001)
	2001
	1st Quarter		2nd Quarter		3rd Quarter		4th Quarter
Concentration in µg/L	Number of CWS	Population Served	Number of CWS	Population Served	Number of CWS	Population Served	Number of CWS	Population Served
Not Sampled	590	3,305,781	587	3,305,623	589	3,305,541	590	3,305,781
<5	0	0	0	0	0	0	0	0
5 - <10	0	0	3	158	1	240	0	0
10 - <202	0	0	0	0	0	0	0	0
20 - <302	0	0	0	0	0	0	0	0
30+2	0	0	0	0	0	0	0	0
1 Community Water System (CWS)   A Community Water System or CWS is defined by the EPA as a public water system that supplies water to the same population year-round.  A public water system is defined as one that provides water for human consumption through a pipe or other constructed conduit to at least fifteen (15) service connectors or serves an average of at least twenty-five (25) people for at least sixty (60) days a year. 2 Maximum Contaminant Level (MCL)  Limits set by the EPA for the presence of contaminants in drinking water; an MCL is the highest amount of a substance allowed under the Clean Water Act. The MCL for Arsenic is 10µg/L. Data Source: Bureau of Water

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Number of Community Water Systems1 (CWS) and Population Served by Mean Arsenic Concentrations (micrograms per liter), by Quarter (2002)
	2002
	1st Quarter		2nd Quarter		3rd Quarter		4th Quarter
Concentration in µg/L	Number of CWS	Population Served	Number of CWS	Population Served	Number of CWS	Population Served	Number of CWS	Population Served
Not Sampled	586	3,296,529	540	2,575,492	531	3,218,010	553	3,185,485
<5	1	5,912	0	0	1	54,309	0	0
5 - <10	8	39,575	55	766,524	62	69,505	41	156,339
10 - <202	0	0	0	0	1	192	1	192
20 - <302	0	0	0	0	0	0	0	0
30+2	0	0	0	0	0	0	0	0
1 Community Water System (CWS)   A Community Water System or CWS is defined by the EPA as a public water system that supplies water to the same population year-round.  A public water system is defined as one that provides water for human consumption through a pipe or other constructed conduit to at least fifteen (15) service connectors or serves an average of at least twenty-five (25) people for at least sixty (60) days a year. 2 Maximum Contaminant Level (MCL)  Limits set by the EPA for the presence of contaminants in drinking water; an MCL is the highest amount of a substance allowed under the Clean Water Act. The MCL for Arsenic is 10µg/L. Data Source: Bureau of Water

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Number of Community Water Systems1 (CWS) and Population Served by Mean Arsenic Concentrations (micrograms per liter), by Quarter (2003)
	2003
	1st Quarter		2nd Quarter		3rd Quarter		4th Quarter
Concentration in µg/L	Number of CWS	Population Served	Number of CWS	Population Served	Number of CWS	Population Served	Number of CWS	Population Served
Not Sampled	526	1,513,301	562	3,216,151	539	3,198,320	523	2,309,978
<5	0	0	0	0	9	72,095	43	940,985
5 - <10	72	1,823,502	36	120,652	51	66,580	33	86,032
10 - <202	1	192	1	192	0	0	0	0
20 - <302	0	0	0	0	0	0	0	0
30+2	0	0	0	0	0	0	0	0
1 Community Water System (CWS)   A Community Water System or CWS is defined by the EPA as a public water system that supplies water to the same population year-round.  A public water system is defined as one that provides water for human consumption through a pipe or other constructed conduit to at least fifteen (15) service connectors or serves an average of at least twenty-five (25) people for at least sixty (60) days a year. 2 Maximum Contaminant Level (MCL)  Limits set by the EPA for the presence of contaminants in drinking water; an MCL is the highest amount of a substance allowed under the Clean Water Act. The MCL for Arsenic is 10µg/L. Data Source: Bureau of Water

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Number of Community Water Systems1 (CWS) and Population Served by Mean Arsenic Concentrations (micrograms per liter), by Quarter (2004)
	2004
	1st Quarter		2nd Quarter		3rd Quarter		4th Quarter
Concentration in µg/L	Number of CWS	Population Served	Number of CWS	Population Served	Number of CWS	Population Served	Number of CWS	Population Served
Not Sampled	510	1,915,764	522	2,159,523	515	2,813,408	512	2,787,612
<5	47	293,303	49	796,772	47	376,223	62	456,735
5 - <10	46	1,172,843	31	425,423	40	192,087	28	137,371
10 - <202	0	0	1	192	1	192	1	192
20 - <302	0	0	0	0	0	0	0	0
30+2	0	0	0	0	0	0	0	0
1 Community Water System (CWS)   A Community Water System or CWS is defined by the EPA as a public water system that supplies water to the same population year-round.  A public water system is defined as one that provides water for human consumption through a pipe or other constructed conduit to at least fifteen (15) service connectors or serves an average of at least twenty-five (25) people for at least sixty (60) days a year. 2 Maximum Contaminant Level (MCL)  Limits set by the EPA for the presence of contaminants in drinking water; an MCL is the highest amount of a substance allowed under the Clean Water Act. The MCL for Arsenic is 10µg/L. Data Source: Bureau of Water

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Number of Community Water Systems1 (CWS) and Population Served by Mean Arsenic Concentrations (micrograms per liter), by Quarter (2005)
	2005
	1st Quarter		2nd Quarter		3rd Quarter		4th Quarter
Concentration in µg/L	Number of CWS	Population Served	Number of CWS	Population Served	Number of CWS	Population Served	Number of CWS	Population Served
Not Sampled	544	2,743,115	530	2,758,529	559	3,168,697	527	2,597,804
<5	61	724,182	75	708,033	46	298,726	79	869,664
5 - <10	1	171	1	906	1	45	0	0
10 - <202	0	0	0	0	0	0	0	0
20 - <302	0	0	0	0	0	0	0	0
30+2	0	0	0	0	0	0	0	0
1 Community Water System (CWS)   A Community Water System or CWS is defined by the EPA as a public water system that supplies water to the same population year-round.  A public water system is defined as one that provides water for human consumption through a pipe or other constructed conduit to at least fifteen (15) service connectors or serves an average of at least twenty-five (25) people for at least sixty (60) days a year. 2 Maximum Contaminant Level (MCL)  Limits set by the EPA for the presence of contaminants in drinking water; an MCL is the highest amount of a substance allowed under the Clean Water Act. The MCL for Arsenic is 10µg/L. Data Source: Bureau of Water

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Number of Community Water Systems1 (CWS) and Population Served by Mean Arsenic Concentrations (micrograms per liter), by Quarter (2006)
	2006
	1st Quarter		2nd Quarter		3rd Quarter		4th Quarter
Concentration in µg/L	Number of CWS	Population Served	Number of CWS	Population Served	Number of CWS	Population Served	Number of CWS	Population Served
Not Sampled	536	1,859,699	557	2,957,357	561	3,318,366	566	2,946,522
<5	69	1,610,349	50	513,441	46	152,432	41	524,276
5 - <10	1	258	0	0	0	0	0	0
10 - <202	1	492	0	0	0	0	0	0
20 - <302	0	0	0	0	0	0	0	0
30+2	0	0	0	0	0	0	0	0
1 Community Water System (CWS)   A Community Water System or CWS is defined by the EPA as a public water system that supplies water to the same population year-round.  A public water system is defined as one that provides water for human consumption through a pipe or other constructed conduit to at least fifteen (15) service connectors or serves an average of at least twenty-five (25) people for at least sixty (60) days a year. 2 Maximum Contaminant Level (MCL)  Limits set by the EPA for the presence of contaminants in drinking water; an MCL is the highest amount of a substance allowed under the Clean Water Act. The MCL for Arsenic is 10µg/L. Data Source: Bureau of Water

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Number of Community Water Systems1 (CWS) and Population Served by Mean Arsenic Concentrations (micrograms per liter), by Quarter (2007)
	2007
	1st Quarter		2nd Quarter		3rd Quarter		4th Quarter
Concentration in µg/L	Number of CWS	Population Served	Number of CWS	Population Served	Number of CWS	Population Served	Number of CWS	Population Served
Not Sampled	576	3,390,728	559	2,728,577	544	2,967,409	600	3,571,376
<5	32	204,667	47	865,724	64	627,986	7	23,970
5 - <10	0	0	1	1,045	0	0	1	49
10 - <202	0	0	1	49	0	0	0	0
20 - <302	0	0	0	0	0	0	0	0
30+2	0	0	0	0	0	0	0	0
1 Community Water System (CWS)   A Community Water System or CWS is defined by the EPA as a public water system that supplies water to the same population year-round.  A public water system is defined as one that provides water for human consumption through a pipe or other constructed conduit to at least fifteen (15) service connectors or serves an average of at least twenty-five (25) people for at least sixty (60) days a year. 2 Maximum Contaminant Level (MCL)  Limits set by the EPA for the presence of contaminants in drinking water; an MCL is the highest amount of a substance allowed under the Clean Water Act. The MCL for Arsenic is 10µg/L. Data Source: Bureau of Water

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Number of Community Water Systems1 (CWS) and Population Served by Mean Arsenic Concentrations (micrograms per liter), by Quarter (2008)
	2008
	1st Quarter		2nd Quarter		3rd Quarter		4th Quarter
Concentration in µg/L	Number of CWS	Population Served	Number of CWS	Population Served	Number of CWS	Population Served	Number of CWS	Population Served
Not Sampled	550	2,282,622	544	2,660,070	540	3,291,565	589	3,430,264
<5	57	1,374,909	63	997,018	66	364,617	19	227,316
5 - <10	1	49	0	0	1	906	0	0
10 - <202	0	0	1	492	1	492	0	0
20 - <302	0	0	0	0	0	0	0	0
30+2	0	0	0	0	0	0	0	0
1 Community Water System (CWS)   A Community Water System or CWS is defined by the EPA as a public water system that supplies water to the same population year-round.  A public water system is defined as one that provides water for human consumption through a pipe or other constructed conduit to at least fifteen (15) service connectors or serves an average of at least twenty-five (25) people for at least sixty (60) days a year. 2 Maximum Contaminant Level (MCL)  Limits set by the EPA for the presence of contaminants in drinking water; an MCL is the highest amount of a substance allowed under the Clean Water Act. The MCL for Arsenic is 10µg/L. Data Source: Bureau of Water

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Number of Community Water Systems1 (CWS) and Population Served by Mean Arsenic Concentrations (micrograms per liter), by Quarter (2009)
	2009
	1st Quarter		2nd Quarter		3rd Quarter		4th Quarter
Concentration in µg/L	Number of CWS	Population Served	Number of CWS	Population Served	Number of CWS	Population Served	Number of CWS	Population Served
Not Sampled	543	2,500,859	563	3,227,338	544	3,527,021	573	3,721,936
<5	64	1,319,248	45	593,261	61	293,308	35	98,663
5 - <10	0	0	0	0	2	202	0	0
10 - <202	1	492	0	0	1	68	0	0
20 - <302	0	0	0	0	0	0	0	0
30+2	0	0	0	0	0	0	0	0
1 Community Water System (CWS)   A Community Water System or CWS is defined by the EPA as a public water system that supplies water to the same population year-round.  A public water system is defined as one that provides water for human consumption through a pipe or other constructed conduit to at least fifteen (15) service connectors or serves an average of at least twenty-five (25) people for at least sixty (60) days a year. 2 Maximum Contaminant Level (MCL)  Limits set by the EPA for the presence of contaminants in drinking water; an MCL is the highest amount of a substance allowed under the Clean Water Act. The MCL for Arsenic is 10µg/L. Data Source: Bureau of Water

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Number of Community Water Systems1 (CWS) and Population Served by Mean Arsenic Concentrations (micrograms per liter), by Quarter (2010)
	2010
	1st Quarter		2nd Quarter		3rd Quarter		4th Quarter
Concentration in µg/L	Number of CWS	Population Served	Number of CWS	Population Served	Number of CWS	Population Served	Number of CWS	Population Served
Not Sampled	534	2,481,539	553	3,234,475	536	3,573,188	568	3,598,347
<5	69	1,378,556	49	625,128	67	286,907	35	261,748
5 - <10	0	0	0	0	0	0	0	0
10 - <202	0	0	1	492	0	0	0	0
20 - <302	0	0	0	0	0	0	0	0
30+2	0	0	0	0	0	0	0	0
1 Community Water System (CWS)   A Community Water System or CWS is defined by the EPA as a public water system that supplies water to the same population year-round.  A public water system is defined as one that provides water for human consumption through a pipe or other constructed conduit to at least fifteen (15) service connectors or serves an average of at least twenty-five (25) people for at least sixty (60) days a year. 2 Maximum Contaminant Level (MCL)  Limits set by the EPA for the presence of contaminants in drinking water; an MCL is the highest amount of a substance allowed under the Clean Water Act. The MCL for Arsenic is 10µg/L. Data Source: Bureau of Water

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Disinfection Byproduct (DBP) Data

THM

Number of Community Water Systems (CWS) and Population Served by Mean THM Concentrations (micrograms per liter), by Year (1999-2002) (2003-2006) (2007-2010)

Number of Community Water Systems1 (CWS) and Population Served by Mean THM2 Concentrations (micrograms per liter), by Year (1999-2002)
	1999		2000		2001		2002
Concentration in µg/L	Number of CWS	Population Served	Number of CWS	Population Served	Number of CWS	Population Served	Number of CWS	Population Served
Not Sampled	515	1,051,706	516	1,052,912	516	1,001,393	538	1,303,927
<20	16	728,739	15	699,380	13	685,735	5	430,462
20 - <40	21	468,862	15	402,035	15	461,825	14	427,252
40 - <60	23	652,528	26	981,952	23	569,467	20	924,990
60 - <80	9	379,332	8	111,541	16	220,094	10	194,861
80 - <1003	2	7,094	7	53,740	3	343,608	4	28,022
100+3	2	15,779	2	3,686	4	23,659	4	32,502
1 Community Water System (CWS)   A Community Water System or CWS is defined by the EPA as a public water system that supplies water to the same population year-round.  A public water system is defined as one that provides water for human consumption through a pipe or other constructed conduit to at least fifteen (15) service connectors or serves an average of at least twenty-five (25) people for at least sixty (60) days a year. 2 Trihalomethanes (THM) are a type of disinfection byproduct that can be found in chlorinated water. Disinfectantion Byproducts (DPB) are chemicals formed when chlorine or other chemicals used to disinfect drinking water sources react with organic (plant or animal) material in the water. These substances are formed during chlorine disinfection and disinfection by chlorinated disinfectants. (See Drinking Water 'About' section for additional information.) 3 Maximum Contaminant Level (MCL)  Limits set by the EPA for the presence of contaminants in drinking water; an MCL is the highest amount of a substance allowed under the Clean Water Act. The MCL for THM is 80µg/L and consists of 4 seperate potential contaminants. Note: DBP violations occur when the average MCL is exceeded for 4 consecutive quarters. Data Source: Bureau of Water

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Number of Community Water Systems1 (CWS) and Population Served by Mean THM2 Concentrations (micrograms per liter), by Year (2003 - 2006)
	2003		2004		2005		2006
Concentration in µg/L	Number of CWS	Population Served	Number of CWS	Population Served	Number of CWS	Population Served	Number of CWS	Population Served
Not Sampled	538	1,227,665	290	669,519	431	927,686	430	892,413
<20	5	496,870	223	1,038,285	92	744,645	91	834,735
20 - <40	17	535,338	43	1,376,464	35	1,230,559	44	1,401,777
40 - <60	25	866,380	28	227,050	37	526,496	33	294,505
60 - <80	10	187,342	11	34,599	9	31,736	7	45,472
80 - <1003	4	23,400	5	25,621	2	6,346	2	1,896
100+3	0	0	3	10,372	0	0	0	0
1 Community Water System (CWS)   A Community Water System or CWS is defined by the EPA as a public water system that supplies water to the same population year-round.  A public water system is defined as one that provides water for human consumption through a pipe or other constructed conduit to at least fifteen (15) service connectors or serves an average of at least twenty-five (25) people for at least sixty (60) days a year. 2 Trihalomethanes (THM) are a type of disinfection byproduct that can be found in chlorinated water. Disinfectantion Byproducts (DPB) are chemicals formed when chlorine or other chemicals used to disinfect drinking water sources react with organic (plant or animal) material in the water. These substances are formed during chlorine disinfection and disinfection by chlorinated disinfectants. (See Drinking Water 'About' section for additional information.) 3 Maximum Contaminant Level (MCL)  Limits set by the EPA for the presence of contaminants in drinking water; an MCL is the highest amount of a substance allowed under the Clean Water Act. The MCL for THM is 80µg/L and consists of 4 seperate potential contaminants. Note: DBP violations occur when the average MCL is exceeded for 4 consecutive quarters. Data Source: Bureau of Water

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Number of Community Water Systems1 (CWS) and Population Served by Mean THM2 Concentrations (micrograms per liter), by Year (2007 - 2010)
	2007		2008		2009		2010
Concentration in µg/L	Number of CWS	Population Served	Number of CWS	Population Served	Number of CWS	Population Served	Number of CWS	Population Served
Not Sampled	448	1,020,058	429	1,014,052	437	998,630	447	1,083,643
<20	83	1,045,518	97	1,114,380	83	1,082,286	74	1,161,373
20 - <40	32	1,084,018	29	1,042,542	38	1,133,688	32	988,819
40 - <60	30	350,088	40	402,062	33	535,678	28	486,004
60 - <80	12	93,774	11	84,374	17	70,317	20	136,139
80 - <1003	3	1,939	1	113	0	0	2	4,117
100+3	0	0	1	57	0	0	0	0
1 Community Water System (CWS)   A Community Water System or CWS is defined by the EPA as a public water system that supplies water to the same population year-round.  A public water system is defined as one that provides water for human consumption through a pipe or other constructed conduit to at least fifteen (15) service connectors or serves an average of at least twenty-five (25) people for at least sixty (60) days a year. 2 Trihalomethanes (THM) are a type of disinfection byproduct that can be found in chlorinated water. Disinfectantion Byproducts (DPB) are chemicals formed when chlorine or other chemicals used to disinfect drinking water sources react with organic (plant or animal) material in the water. These substances are formed during chlorine disinfection and disinfection by chlorinated disinfectants. (See Drinking Water 'About' section for additional information.) 3 Maximum Contaminant Level (MCL)  Limits set by the EPA for the presence of contaminants in drinking water; an MCL is the highest amount of a substance allowed under the Clean Water Act. The MCL for THM is 80µg/L and consists of 4 seperate potential contaminants. Note: DBP violations occur when the average MCL is exceeded for 4 consecutive quarters. Data Source: Bureau of Water

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Number of Community Water Systems (CWS) and Population Served by Max THM Concentrations (micrograms per liter), by Year (1999-2002) (2003-2006) (2007-2010)

Number of Community Water Systems1 (CWS) and Population Served by Max THM2 Concentrations (micrograms per liter), by Year (1999-2002)
	1999		2000		2001		2002
Concentration in µg/L	Number of CWS	Population Served	Number of CWS	Population Served	Number of CWS	Population Served	Number of CWS	Population Served
Not Sampled	515	1,051,706	516	1,052,912	516	1,001,393	538	1,303,927
<20	14	399,339	13	388,855	12	375,235	3	114,368
20 - <40	4	410,606	7	445,841	4	370,664	7	425,400
40 - <60	20	528,091	20	746,953	17	656,337	15	695,404
60 - <80	21	507,316	15	502,782	17	316,769	13	527,325
80 - <1003	6	52,085	10	124,224	13	525,545	7	134,857
100+3	8	354,897	8	43,679	11	59,838	12	140,735
1 Community Water System (CWS)   A Community Water System or CWS is defined by the EPA as a public water system that supplies water to the same population year-round.  A public water system is defined as one that provides water for human consumption through a pipe or other constructed conduit to at least fifteen (15) service connectors or serves an average of at least twenty-five (25) people for at least sixty (60) days a year. 2 Trihalomethanes (THM) are a type of disinfection byproduct that can be found in chlorinated water. Disinfectantion Byproducts (DPB) are chemicals formed when chlorine or other chemicals used to disinfect drinking water sources react with organic (plant or animal) material in the water. These substances are formed during chlorine disinfection and disinfection by chlorinated disinfectants. (See Drinking Water 'About' section for additional information.) 3 Maximum Contaminant Level (MCL)  Limits set by the EPA for the presence of contaminants in drinking water; an MCL is the highest amount of a substance allowed under the Clean Water Act. The MCL for THM is 80µg/L and consists of 4 seperate potential contaminants. Note: DBP violations occur when the average MCL is exceeded for 4 consecutive quarters. Data Source: Bureau of Water

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Number of Community Water Systems1 (CWS) and Population Served by Max THM2 Concentrations (micrograms per liter), by Year (2003 - 2006)
	2003		2004		2005		2006
Concentration in µg/L	Number of CWS	Population Served	Number of CWS	Population Served	Number of CWS	Population Served	Number of CWS	Population Served
Not Sampled	538	1,227,665	290	669,519	431	927,686	430	892,413
<20	2	372,077	214	448,475	89	670,343	85	716,524
20 - <40	7	171,130	33	1,159,279	18	494,226	34	848,976
40 - <60	20	756,614	25	397,249	25	596,165	26	745,650
60 - <80	16	599,501	20	497,520	24	564,218	21	188,417
80 - <1003	7	69,149	9	59,961	14	194,368	9	64,818
100+3	9	140,859	12	149,907	5	20,462	2	14,000
1 Community Water System (CWS)   A Community Water System or CWS is defined by the EPA as a public water system that supplies water to the same population year-round.  A public water system is defined as one that provides water for human consumption through a pipe or other constructed conduit to at least fifteen (15) service connectors or serves an average of at least twenty-five (25) people for at least sixty (60) days a year. 2 Trihalomethanes (THM) are a type of disinfection byproduct that can be found in chlorinated water. Disinfectantion Byproducts (DPB) are chemicals formed when chlorine or other chemicals used to disinfect drinking water sources react with organic (plant or animal) material in the water. These substances are formed during chlorine disinfection and disinfection by chlorinated disinfectants. (See Drinking Water 'About' section for additional information.) 3 Maximum Contaminant Level (MCL)  Limits set by the EPA for the presence of contaminants in drinking water; an MCL is the highest amount of a substance allowed under the Clean Water Act. The MCL for THM is 80µg/L and consists of 4 seperate potential contaminants. Note: DBP violations occur when the average MCL is exceeded for 4 consecutive quarters. Data Source: Bureau of Water

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Number of Community Water Systems1 (CWS) and Population Served by Max THM2 Concentrations (micrograms per liter), by Year (2007 - 2010)
	2007		2008		2009		2010
Concentration in µg/L	Number of CWS	Population Served	Number of CWS	Population Served	Number of CWS	Population Served	Number of CWS	Population Served
Not Sampled	448	1,020,058	429	1,014,052	437	998,630	447	1,083,643
<20	76	654,703	87	615,798	73	272,935	64	657,394
20 - <40	24	1,064,891	22	755,646	26	1,327,391	27	1,212,290
40 - <60	21	524,875	34	912,847	30	873,842	28	642,890
60 - <80	19	142,211	20	304,994	27	266,636	20	196,122
80 - <1003	12	153,833	9	37,682	11	74,439	9	40,500
100+3	8	34,824	7	16,561	4	6,726	8	27,256
1 Community Water System (CWS)   A Community Water System or CWS is defined by the EPA as a public water system that supplies water to the same population year-round.  A public water system is defined as one that provides water for human consumption through a pipe or other constructed conduit to at least fifteen (15) service connectors or serves an average of at least twenty-five (25) people for at least sixty (60) days a year. 2 Trihalomethanes (THM) are a type of disinfection byproduct that can be found in chlorinated water. Disinfectantion Byproducts (DPB) are chemicals formed when chlorine or other chemicals used to disinfect drinking water sources react with organic (plant or animal) material in the water. These substances are formed during chlorine disinfection and disinfection by chlorinated disinfectants. (See Drinking Water 'About' section for additional information.) 3 Maximum Contaminant Level (MCL)  Limits set by the EPA for the presence of contaminants in drinking water; an MCL is the highest amount of a substance allowed under the Clean Water Act. The MCL for THM is 80µg/L and consists of 4 seperate potential contaminants. Note: DBP violations occur when the average MCL is exceeded for 4 consecutive quarters. Data Source: Bureau of Water

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Number of Community Water Systems (CWS) and Population Served by Mean THM Concentrations (micrograms per liter), by Quarter (1999) (2000) (2001) (2002) (2003) (2004) (2005) (2006) (2007) (2008) (2009) (2010)

Number of Community Water Systems1 (CWS) and Population Served by Mean THM2 Concentrations (micrograms per liter), by Quarter (1999)
	1999
	1st Quarter		2nd Quarter		3rd Quarter		4th Quarter
Concentration in µg/L	Number of CWS	Population Served	Number of CWS	Population Served	Number of CWS	Population Served	Number of CWS	Population Served
Not Sampled	518	1,065,876	516	1,066,188	519	1,118,341	515	1,051,706
<20	20	785,696	14	384,882	19	508,389	21	765,623
20 - <40	23	587,654	12	569,525	10	498,824	18	398,782
40 - <60	20	493,316	26	1,134,482	14	428,209	18	558,934
60 - <80	6	356,517	13	109,384	15	360,846	10	490,929
80 - <1003	1	14,981	4	16,751	6	39,085	4	35,768
100+3	0	0	3	22,828	5	350,346	2	2,298
1 Community Water System (CWS)   A Community Water System or CWS is defined by the EPA as a public water system that supplies water to the same population year-round.  A public water system is defined as one that provides water for human consumption through a pipe or other constructed conduit to at least fifteen (15) service connectors or serves an average of at least twenty-five (25) people for at least sixty (60) days a year. 2 Trihalomethanes (THM) are a type of disinfection byproduct that can be found in chlorinated water. Disinfectantion Byproducts (DPB) are chemicals formed when chlorine or other chemicals used to disinfect drinking water sources react with organic (plant or animal) material in the water. These substances are formed during chlorine disinfection and disinfection by chlorinated disinfectants. (See Drinking Water 'About' section for additional information.) 3 Maximum Contaminant Level (MCL)  Limits set by the EPA for the presence of contaminants in drinking water; an MCL is the highest amount of a substance allowed under the Clean Water Act. The MCL for THM is 80µg/L and consists of 4 seperate potential contaminants. Note: DBP violations occur when the average MCL is exceeded for 4 consecutive quarters. Data Source: Bureau of Water

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Number of Community Water Systems1 (CWS) and Population Served by Mean THM2 Concentrations (micrograms per liter), by Quarter (2000)
	2000
	1st Quarter		2nd Quarter		3rd Quarter		4th Quarter
Concentration in µg/L	Number of CWS	Population Served	Number of CWS	Population Served	Number of CWS	Population Served	Number of CWS	Population Served
Not Sampled	516	1,052,912	516	1,052,912	518	1,063,716	517	1,056,197
<20	20	1,110,641	18	420,710	15	399,364	16	703,503
20 - <40	31	896,359	17	731,386	7	486,254	20	739,943
40 - <60	14	169,670	18	938,448	20	718,943	20	691,909
60 - <80	3	50,384	12	107,736	12	476,585	7	50,743
80 - <1003	5	25,280	6	50,368	9	116,705	7	59,265
100+3	0	0	2	3,686	8	43,679	2	3,686
1 Community Water System (CWS)   A Community Water System or CWS is defined by the EPA as a public water system that supplies water to the same population year-round.  A public water system is defined as one that provides water for human consumption through a pipe or other constructed conduit to at least fifteen (15) service connectors or serves an average of at least twenty-five (25) people for at least sixty (60) days a year. 2 Trihalomethanes (THM) are a type of disinfection byproduct that can be found in chlorinated water. Disinfectantion Byproducts (DPB) are chemicals formed when chlorine or other chemicals used to disinfect drinking water sources react with organic (plant or animal) material in the water. These substances are formed during chlorine disinfection and disinfection by chlorinated disinfectants. (See Drinking Water 'About' section for additional information.) 3 Maximum Contaminant Level (MCL)  Limits set by the EPA for the presence of contaminants in drinking water; an MCL is the highest amount of a substance allowed under the Clean Water Act. The MCL for THM is 80µg/L and consists of 4 seperate potential contaminants. Note: DBP violations occur when the average MCL is exceeded for 4 consecutive quarters. Data Source: Bureau of Water

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Number of Community Water Systems1 (CWS) and Population Served by Mean THM2 Concentrations (micrograms per liter), by Quarter (2001)
	2001
	1st Quarter		2nd Quarter		3rd Quarter		4th Quarter
Concentration in µg/L	Number of CWS	Population Served	Number of CWS	Population Served	Number of CWS	Population Served	Number of CWS	Population Served
Not Sampled	517	1,029,773	520	1,065,693	523	1,161,228	516	988,571
<20	18	774,609	11	355,823	9	261,987	17	726,277
20 - <40	31	843,965	14	678,999	9	538,862	13	233,566
40 - <60	15	577,971	20	575,596	19	545,052	27	1,149,648
60 - <80	3	52,725	8	117,359	13	300,394	12	141,651
80 - <1003	4	23,052	10	479,244	10	448,626	4	51,054
100+3	2	3,686	7	33,067	7	49,632	1	15,014
1 Community Water System (CWS)   A Community Water System or CWS is defined by the EPA as a public water system that supplies water to the same population year-round.  A public water system is defined as one that provides water for human consumption through a pipe or other constructed conduit to at least fifteen (15) service connectors or serves an average of at least twenty-five (25) people for at least sixty (60) days a year. 2 Trihalomethanes (THM) are a type of disinfection byproduct that can be found in chlorinated water. Disinfectantion Byproducts (DPB) are chemicals formed when chlorine or other chemicals used to disinfect drinking water sources react with organic (plant or animal) material in the water. These substances are formed during chlorine disinfection and disinfection by chlorinated disinfectants. (See Drinking Water 'About' section for additional information.) 3 Maximum Contaminant Level (MCL)  Limits set by the EPA for the presence of contaminants in drinking water; an MCL is the highest amount of a substance allowed under the Clean Water Act. The MCL for THM is 80µg/L and consists of 4 seperate potential contaminants. Note: DBP violations occur when the average MCL is exceeded for 4 consecutive quarters. Data Source: Bureau of Water

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Number of Community Water Systems1 (CWS) and Population Served by Mean THM2 Concentrations (micrograms per liter), by Quarter (2002)
	2002
	1st Quarter		2nd Quarter		3rd Quarter		4th Quarter
Concentration in µg/L	Number of CWS	Population Served	Number of CWS	Population Served	Number of CWS	Population Served	Number of CWS	Population Served
Not Sampled	540	1,299,134	540	1,302,982	539	1,318,908	540	1,318,967
<20	5	469,989	2	114,309	4	424,868	5	456,491
20 - <40	27	1,112,553	11	603,265	10	235,360	18	899,903
40 - <60	13	312,167	22	1,096,152	16	680,183	13	409,859
60 - <80	7	108,001	11	74,737	11	498,482	5	94,023
80 - <1003	1	22,270	4	48,445	7	93,038	10	126,841
100+3	2	17,902	5	102,126	8	91,177	4	35,932
1 Community Water System (CWS)   A Community Water System or CWS is defined by the EPA as a public water system that supplies water to the same population year-round.  A public water system is defined as one that provides water for human consumption through a pipe or other constructed conduit to at least fifteen (15) service connectors or serves an average of at least twenty-five (25) people for at least sixty (60) days a year. 2 Trihalomethanes (THM) are a type of disinfection byproduct that can be found in chlorinated water. Disinfectantion Byproducts (DPB) are chemicals formed when chlorine or other chemicals used to disinfect drinking water sources react with organic (plant or animal) material in the water. These substances are formed during chlorine disinfection and disinfection by chlorinated disinfectants. (See Drinking Water 'About' section for additional information.) 3 Maximum Contaminant Level (MCL)  Limits set by the EPA for the presence of contaminants in drinking water; an MCL is the highest amount of a substance allowed under the Clean Water Act. The MCL for THM is 80µg/L and consists of 4 seperate potential contaminants. Note: DBP violations occur when the average MCL is exceeded for 4 consecutive quarters. Data Source: Bureau of Water

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Number of Community Water Systems1 (CWS) and Population Served by Mean THM2 Concentrations (micrograms per liter), by Quarter (2003)
	2003
	1st Quarter		2nd Quarter		3rd Quarter		4th Quarter
Concentration in µg/L	Number of CWS	Population Served	Number of CWS	Population Served	Number of CWS	Population Served	Number of CWS	Population Served
Not Sampled	539	1,230,780	540	1,262,119	539	1,228,358	538	1,227,665
<20	10	636,853	4	442,561	9	513,921	6	451,854
20 - <40	23	799,654	10	185,573	9	199,104	22	773,930
40 - <60	20	569,181	26	1,190,491	19	766,220	25	779,171
60 - <80	4	45,789	9	139,146	14	565,912	6	99,449
80 - <1003	3	54,738	5	20,570	3	11,744	1	2,038
100+3	0	0	5	96,535	6	51,736	1	2,888
1 Community Water System (CWS)   A Community Water System or CWS is defined by the EPA as a public water system that supplies water to the same population year-round.  A public water system is defined as one that provides water for human consumption through a pipe or other constructed conduit to at least fifteen (15) service connectors or serves an average of at least twenty-five (25) people for at least sixty (60) days a year. 2 Trihalomethanes (THM) are a type of disinfection byproduct that can be found in chlorinated water. Disinfectantion Byproducts (DPB) are chemicals formed when chlorine or other chemicals used to disinfect drinking water sources react with organic (plant or animal) material in the water. These substances are formed during chlorine disinfection and disinfection by chlorinated disinfectants. (See Drinking Water 'About' section for additional information.) 3 Maximum Contaminant Level (MCL)  Limits set by the EPA for the presence of contaminants in drinking water; an MCL is the highest amount of a substance allowed under the Clean Water Act. The MCL for THM is 80µg/L and consists of 4 seperate potential contaminants. Note: DBP violations occur when the average MCL is exceeded for 4 consecutive quarters. Data Source: Bureau of Water

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Number of Community Water Systems1 (CWS) and Population Served by Mean THM2 Concentrations (micrograms per liter), by Quarter (2004)
	2004
	1st Quarter		2nd Quarter		3rd Quarter		4th Quarter
Concentration in µg/L	Number of CWS	Population Served	Number of CWS	Population Served	Number of CWS	Population Served	Number of CWS	Population Served
Not Sampled	521	1,019,263	459	853,688	347	808,990	514	968,508
<20	29	1,433,748	63	793,164	175	551,982	21	1,153,884
20 - <40	39	840,505	39	1,030,868	31	1,526,108	30	879,765
40 - <60	8	68,505	20	298,989	17	246,948	20	284,445
60 - <80	4	11,089	14	360,818	14	168,806	14	85,782
80 - <1003	0	0	6	40,997	8	46,911	1	1,425
100+3	2	8,800	2	3,386	11	32,165	3	8,101
1 Community Water System (CWS)   A Community Water System or CWS is defined by the EPA as a public water system that supplies water to the same population year-round.  A public water system is defined as one that provides water for human consumption through a pipe or other constructed conduit to at least fifteen (15) service connectors or serves an average of at least twenty-five (25) people for at least sixty (60) days a year. 2 Trihalomethanes (THM) are a type of disinfection byproduct that can be found in chlorinated water. Disinfectantion Byproducts (DPB) are chemicals formed when chlorine or other chemicals used to disinfect drinking water sources react with organic (plant or animal) material in the water. These substances are formed during chlorine disinfection and disinfection by chlorinated disinfectants. (See Drinking Water 'About' section for additional information.) 3 Maximum Contaminant Level (MCL)  Limits set by the EPA for the presence of contaminants in drinking water; an MCL is the highest amount of a substance allowed under the Clean Water Act. The MCL for THM is 80µg/L and consists of 4 seperate potential contaminants. Note: DBP violations occur when the average MCL is exceeded for 4 consecutive quarters. Data Source: Bureau of Water

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Number of Community Water Systems1 (CWS) and Population Served by Mean THM2 Concentrations (micrograms per liter), by Quarter (2005)
	2005
	1st Quarter		2nd Quarter		3rd Quarter		4th Quarter
Concentration in µg/L	Number of CWS	Population Served	Number of CWS	Population Served	Number of CWS	Population Served	Number of CWS	Population Served
Not Sampled	525	1,124,787	531	1,222,587	433	885,800	529	1,187,363
<20	24	1,398,369	12	559,804	93	725,508	15	913,448
20 - <40	42	788,701	26	1,154,050	22	736,160	26	1,008,338
40 - <60	11	135,749	29	463,993	23	395,354	22	244,299
60 - <80	1	1,651	6	57,404	24	578,059	9	64,082
80 - <1003	3	18,211	1	8,380	8	133,885	3	37,516
100+3	0	0	1	1,250	3	12,702	2	12,422
1 Community Water System (CWS)   A Community Water System or CWS is defined by the EPA as a public water system that supplies water to the same population year-round.  A public water system is defined as one that provides water for human consumption through a pipe or other constructed conduit to at least fifteen (15) service connectors or serves an average of at least twenty-five (25) people for at least sixty (60) days a year. 2 Trihalomethanes (THM) are a type of disinfection byproduct that can be found in chlorinated water. Disinfectantion Byproducts (DPB) are chemicals formed when chlorine or other chemicals used to disinfect drinking water sources react with organic (plant or animal) material in the water. These substances are formed during chlorine disinfection and disinfection by chlorinated disinfectants. (See Drinking Water 'About' section for additional information.) 3 Maximum Contaminant Level (MCL)  Limits set by the EPA for the presence of contaminants in drinking water; an MCL is the highest amount of a substance allowed under the Clean Water Act. The MCL for THM is 80µg/L and consists of 4 seperate potential contaminants. Note: DBP violations occur when the average MCL is exceeded for 4 consecutive quarters. Data Source: Bureau of Water

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Number of Community Water Systems1 (CWS) and Population Served by Mean THM2 Concentrations (micrograms per liter), by Quarter (2006)
	2006
	1st Quarter		2nd Quarter		3rd Quarter		4th Quarter
Concentration in µg/L	Number of CWS	Population Served	Number of CWS	Population Served	Number of CWS	Population Served	Number of CWS	Population Served
Not Sampled	530	1,227,022	514	1,198,548	444	906,305	528	1,235,551
<20	19	1,183,758	26	823,953	78	727,919	13	829,319
20 - <40	43	885,539	31	983,749	33	890,244	40	1,218,179
40 - <60	12	135,554	28	396,216	24	707,839	20	153,234
60 - <80	2	15,651	7	67,386	18	182,947	3	21,378
80 - <1003	1	23,274	1	946	9	42,494	2	12,187
100+3	0	0	0	0	1	13,050	1	950
1 Community Water System (CWS)   A Community Water System or CWS is defined by the EPA as a public water system that supplies water to the same population year-round.  A public water system is defined as one that provides water for human consumption through a pipe or other constructed conduit to at least fifteen (15) service connectors or serves an average of at least twenty-five (25) people for at least sixty (60) days a year. 2 Trihalomethanes (THM) are a type of disinfection byproduct that can be found in chlorinated water. Disinfectantion Byproducts (DPB) are chemicals formed when chlorine or other chemicals used to disinfect drinking water sources react with organic (plant or animal) material in the water. These substances are formed during chlorine disinfection and disinfection by chlorinated disinfectants. (See Drinking Water 'About' section for additional information.) 3 Maximum Contaminant Level (MCL)  Limits set by the EPA for the presence of contaminants in drinking water; an MCL is the highest amount of a substance allowed under the Clean Water Act. The MCL for THM is 80µg/L and consists of 4 seperate potential contaminants. Note: DBP violations occur when the average MCL is exceeded for 4 consecutive quarters. Data Source: Bureau of Water

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Number of Community Water Systems1 (CWS) and Population Served by Mean THM2 Concentrations (micrograms per liter), by Quarter (2007)
	2007
	1st Quarter		2nd Quarter		3rd Quarter		4th Quarter
Concentration in µg/L	Number of CWS	Population Served	Number of CWS	Population Served	Number of CWS	Population Served	Number of CWS	Population Served
Not Sampled	529	1,250,340	496	1,211,554	481	1,019,032	529	1,260,681
<20	18	895,284	45	877,156	51	733,242	12	799,143
20 - <40	40	1,185,937	27	1,046,550	26	1,205,797	28	1,124,829
40 - <60	16	241,110	17	316,779	19	392,726	21	251,562
60 - <80	5	22,724	17	121,321	15	108,527	13	118,998
80 - <1003	0	0	6	22,035	9	102,197	4	39,232
100+3	0	0	0	0	7	33,874	1	950
1 Community Water System (CWS)   A Community Water System or CWS is defined by the EPA as a public water system that supplies water to the same population year-round.  A public water system is defined as one that provides water for human consumption through a pipe or other constructed conduit to at least fifteen (15) service connectors or serves an average of at least twenty-five (25) people for at least sixty (60) days a year. 2 Trihalomethanes (THM) are a type of disinfection byproduct that can be found in chlorinated water. Disinfectantion Byproducts (DPB) are chemicals formed when chlorine or other chemicals used to disinfect drinking water sources react with organic (plant or animal) material in the water. These substances are formed during chlorine disinfection and disinfection by chlorinated disinfectants. (See Drinking Water 'About' section for additional information.) 3 Maximum Contaminant Level (MCL)  Limits set by the EPA for the presence of contaminants in drinking water; an MCL is the highest amount of a substance allowed under the Clean Water Act. The MCL for THM is 80µg/L and consists of 4 seperate potential contaminants. Note: DBP violations occur when the average MCL is exceeded for 4 consecutive quarters. Data Source: Bureau of Water

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Number of Community Water Systems1 (CWS) and Population Served by Mean THM2 Concentrations (micrograms per liter), by Quarter (2008)
	2008
	1st Quarter		2nd Quarter		3rd Quarter		4th Quarter
Concentration in µg/L	Number of CWS	Population Served	Number of CWS	Population Served	Number of CWS	Population Served	Number of CWS	Population Served
Not Sampled	529	1,291,742	481	1,121,804	475	1,117,169	529	1,291,742
<20	16	1,196,322	53	709,008	49	835,729	9	743,285
20 - <40	41	932,962	22	1,235,804	26	619,663	27	1,079,566
40 - <60	16	190,662	37	386,489	30	873,693	29	403,615
60 - <80	5	39,278	13	204,337	16	163,924	11	130,764
80 - <1003	0	0	1	113	7	37,480	3	8,608
100+3	1	6,614	1	25	5	9,922	0	0
1 Community Water System (CWS)   A Community Water System or CWS is defined by the EPA as a public water system that supplies water to the same population year-round.  A public water system is defined as one that provides water for human consumption through a pipe or other constructed conduit to at least fifteen (15) service connectors or serves an average of at least twenty-five (25) people for at least sixty (60) days a year. 2 Trihalomethanes (THM) are a type of disinfection byproduct that can be found in chlorinated water. Disinfectantion Byproducts (DPB) are chemicals formed when chlorine or other chemicals used to disinfect drinking water sources react with organic (plant or animal) material in the water. These substances are formed during chlorine disinfection and disinfection by chlorinated disinfectants. (See Drinking Water 'About' section for additional information.) 3 Maximum Contaminant Level (MCL)  Limits set by the EPA for the presence of contaminants in drinking water; an MCL is the highest amount of a substance allowed under the Clean Water Act. The MCL for THM is 80µg/L and consists of 4 seperate potential contaminants. Note: DBP violations occur when the average MCL is exceeded for 4 consecutive quarters. Data Source: Bureau of Water

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Number of Community Water Systems1 (CWS) and Population Served by Mean THM2 Concentrations (micrograms per liter), by Quarter (2009)
	2009
	1st Quarter		2nd Quarter		3rd Quarter		4th Quarter
Concentration in µg/L	Number of CWS	Population Served	Number of CWS	Population Served	Number of CWS	Population Served	Number of CWS	Population Served
Not Sampled	528	1,372,007	498	1,193,967	467	1,176,670	529	1,374,167
<20	15	922,325	31	430,993	57	657,525	16	1,118,066
20 - <40	38	1,249,044	32	1,476,642	23	908,543	26	839,780
40 - <60	22	230,782	30	606,395	27	810,353	29	441,638
60 - <80	5	46,441	15	93,776	22	205,194	7	46,923
80 - <1003	0	0	2	18,826	9	55,613	0	0
100+3	0	0	0	0	3	6,701	1	25
1 Community Water System (CWS)   A Community Water System or CWS is defined by the EPA as a public water system that supplies water to the same population year-round.  A public water system is defined as one that provides water for human consumption through a pipe or other constructed conduit to at least fifteen (15) service connectors or serves an average of at least twenty-five (25) people for at least sixty (60) days a year. 2 Trihalomethanes (THM) are a type of disinfection byproduct that can be found in chlorinated water. Disinfectantion Byproducts (DPB) are chemicals formed when chlorine or other chemicals used to disinfect drinking water sources react with organic (plant or animal) material in the water. These substances are formed during chlorine disinfection and disinfection by chlorinated disinfectants. (See Drinking Water 'About' section for additional information.) 3 Maximum Contaminant Level (MCL)  Limits set by the EPA for the presence of contaminants in drinking water; an MCL is the highest amount of a substance allowed under the Clean Water Act. The MCL for THM is 80µg/L and consists of 4 seperate potential contaminants. Note: DBP violations occur when the average MCL is exceeded for 4 consecutive quarters. Data Source: Bureau of Water

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Number of Community Water Systems1 (CWS) and Population Served by Mean THM2 Concentrations (micrograms per liter), by Quarter (2010)
	2010
	1st Quarter		2nd Quarter		3rd Quarter		4th Quarter
Concentration in µg/L	Number of CWS	Population Served	Number of CWS	Population Served	Number of CWS	Population Served	Number of CWS	Population Served
Not Sampled	524	1,403,050	510	1,284,852	460	1,201,537	525	1,403,559
<20	18	1,337,133	20	849,406	61	710,119	13	892,741
20 - <40	37	832,413	31	1,092,564	22	1,068,997	20	883,958
40 - <60	17	238,361	28	577,767	28	637,126	27	537,797
60 - <80	7	49,138	12	53,742	18	192,410	10	93,752
80 - <1003	0	0	2	1,764	9	42,628	4	25,143
100+3	0	0	0	0	5	7,278	4	23,145
1 Community Water System (CWS)   A Community Water System or CWS is defined by the EPA as a public water system that supplies water to the same population year-round.  A public water system is defined as one that provides water for human consumption through a pipe or other constructed conduit to at least fifteen (15) service connectors or serves an average of at least twenty-five (25) people for at least sixty (60) days a year. 2 Trihalomethanes (THM) are a type of disinfection byproduct that can be found in chlorinated water. Disinfectantion Byproducts (DPB) are chemicals formed when chlorine or other chemicals used to disinfect drinking water sources react with organic (plant or animal) material in the water. These substances are formed during chlorine disinfection and disinfection by chlorinated disinfectants. (See Drinking Water 'About' section for additional information.) 3 Maximum Contaminant Level (MCL)  Limits set by the EPA for the presence of contaminants in drinking water; an MCL is the highest amount of a substance allowed under the Clean Water Act. The MCL for THM is 80µg/L and consists of 4 seperate potential contaminants. Note: DBP violations occur when the average MCL is exceeded for 4 consecutive quarters. Data Source: Bureau of Water

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HAA5

Number of Community Water Systems (CWS) and Population Served by Mean HAA5 Concentrations (micrograms per liter), by Year (1999-2002) (2003-2006) (2007-2010)

Number of Community Water Systems1 (CWS) and Population Served by Mean HAA52 Concentrations (micrograms per liter), by Year (1999-2002)
	1999		2000		2001		2002
Concentration in µg/L	Number of CWS	Population Served	Number of CWS	Population Served	Number of CWS	Population Served	Number of CWS	Population Served
Not Sampled	515	1,051,706	516	1,052,912	516	990,528	538	1,279,857
<15	14	399,339	14	699,355	11	315,235	2	114,309
15 - <30	8	450,982	9	153,823	4	386,373	5	381,474
30 - <45	15	348,747	20	702,531	21	530,341	19	903,193
45 - <60	22	628,791	14	528,456	17	492,363	10	348,104
60 - <753	6	44,936	7	98,441	10	511,088	12	240,055
75+3	8	379,539	9	69,728	11	79,853	9	75,024
1 Community Water System (CWS)   A Community Water System or CWS is defined by the EPA as a public water system that supplies water to the same population year-round.  A public water system is defined as one that provides water for human consumption through a pipe or other constructed conduit to at least fifteen (15) service connectors or serves an average of at least twenty-five (25) people for at least sixty (60) days a year. 2 Halogenic acetic acids (HAA5) are a type of disinfection byproduct that can be found in chlorinated water. Disinfectantion Byproducts (DPB) are chemicals formed when chlorine or other chemicals used to disinfect drinking water sources react with organic (plant or animal) material in the water. These substances are formed during chlorine disinfection and disinfection by chlorinated disinfectants. (See Drinking Water 'About' section for additional information.) 3 Maximum Contaminant Level (MCL)  Limits set by the EPA for the presence of contaminants in drinking water; an MCL is the highest amount of a substance allowed under the Clean Water Act. The MCL for HAA5 is 60µg/L and consists of 4 seperate potential contaminants. Note: DBP violations occur when the average MCL is exceeded for 4 consecutive quarters. Data Source: Bureau of Water

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Number of Community Water Systems1 (CWS) and Population Served by Mean HAA52 Concentrations (micrograms per liter), by Year (2003-2006)
	2003		2004		2005		2006
Concentration in µg/L	Number of CWS	Population Served	Number of CWS	Population Served	Number of CWS	Population Served	Number of CWS	Population Served
Not Sampled	538	1,227,665	291	707,540	430	871,459	429	878,777
<15	2	115,886	228	690,650	105	828,417	104	817,440
15 - <30	8	476,786	37	1,354,648	33	1,134,032	40	1,138,953
30 - <45	20	651,124	39	574,600	30	562,191	29	617,697
45 - <60	19	716,662	6	47,402	7	67,831	4	15,176
60 - <753	6	120,679	2	7,070	1	3,538	1	2,755
75+3	6	28,193	0	0	0	0	0	0
1 Community Water System (CWS)   A Community Water System or CWS is defined by the EPA as a public water system that supplies water to the same population year-round.  A public water system is defined as one that provides water for human consumption through a pipe or other constructed conduit to at least fifteen (15) service connectors or serves an average of at least twenty-five (25) people for at least sixty (60) days a year. 2 Halogenic acetic acids (HAA5) are a type of disinfection byproduct that can be found in chlorinated water. Disinfectantion Byproducts (DPB) are chemicals formed when chlorine or other chemicals used to disinfect drinking water sources react with organic (plant or animal) material in the water. These substances are formed during chlorine disinfection and disinfection by chlorinated disinfectants. (See Drinking Water 'About' section for additional information.) 3 Maximum Contaminant Level (MCL)  Limits set by the EPA for the presence of contaminants in drinking water; an MCL is the highest amount of a substance allowed under the Clean Water Act. The MCL for HAA5 is 60µg/L and consists of 4 seperate potential contaminants. Note: DBP violations occur when the average MCL is exceeded for 4 consecutive quarters. Data Source: Bureau of Water

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Number of Community Water Systems1 (CWS) and Population Served by Mean HAA52 Concentrations (micrograms per liter), by Year (2007-2010)
	2007		2008		2009		2010
Concentration in µg/L	Number of CWS	Population Served	Number of CWS	Population Served	Number of CWS	Population Served	Number of CWS	Population Served
Not Sampled	445	949,635	427	944,747	439	1,000,176	444	1,080,268
<15	90	807,363	105	834,658	87	844,931	83	796,302
15 - <30	30	801,011	25	921,126	30	962,167	41	1,137,232
30 - <45	36	983,489	41	839,426	37	876,192	26	752,692
45 - <60	6	52,947	10	117,623	14	137,065	9	93,601
60 - <753	1	950	0	0	1	68	0	0
75+3	0	0	0	0	0	0	0	0
1 Community Water System (CWS)   A Community Water System or CWS is defined by the EPA as a public water system that supplies water to the same population year-round.  A public water system is defined as one that provides water for human consumption through a pipe or other constructed conduit to at least fifteen (15) service connectors or serves an average of at least twenty-five (25) people for at least sixty (60) days a year. 2 Halogenic acetic acids (HAA5) are a type of disinfection byproduct that can be found in chlorinated water. Disinfectantion Byproducts (DPB) are chemicals formed when chlorine or other chemicals used to disinfect drinking water sources react with organic (plant or animal) material in the water. These substances are formed during chlorine disinfection and disinfection by chlorinated disinfectants. (See Drinking Water 'About' section for additional information.) 3 Maximum Contaminant Level (MCL)  Limits set by the EPA for the presence of contaminants in drinking water; an MCL is the highest amount of a substance allowed under the Clean Water Act. The MCL for HAA5 is 60µg/L and consists of 4 seperate potential contaminants. Note: DBP violations occur when the average MCL is exceeded for 4 consecutive quarters. Data Source: Bureau of Water

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Number of Community Water Systems (CWS) and Population Served by Max HAA5 Concentrations (micrograms per liter), by Year (1999-2002) (2003-2006) (2007-2010)

Number of Community Water Systems1 (CWS) and Population Served by Max HAA52 Concentrations (micrograms per liter), by Year (1999-2002)
	1999		2000		2001		2002
Concentration in µg/L	Number of CWS	Population Served	Number of CWS	Population Served	Number of CWS	Population Served	Number of CWS	Population Served
Not Sampled	515	1,051,706	516	1,052,912	516	990,528	538	1,279,857
<15	13	339,339	13	388,855	10	291,106	1	54,309
15 - <30	4	384,646	2	14,013	3	394,629	3	394,629
30 - <45	10	194,099	10	568,913	8	215,895	9	205,683
45 - <60	11	419,952	14	570,268	16	534,622	13	619,501
60 - <753	20	504,428	13	473,355	14	259,026	10	452,154
75+3	15	409,870	21	236,930	23	619,975	21	335,883
1 Community Water System (CWS)   A Community Water System or CWS is defined by the EPA as a public water system that supplies water to the same population year-round.  A public water system is defined as one that provides water for human consumption through a pipe or other constructed conduit to at least fifteen (15) service connectors or serves an average of at least twenty-five (25) people for at least sixty (60) days a year. 2 Halogenic acetic acids (HAA5) are a type of disinfection byproduct that can be found in chlorinated water. Disinfectantion Byproducts (DPB) are chemicals formed when chlorine or other chemicals used to disinfect drinking water sources react with organic (plant or animal) material in the water. These substances are formed during chlorine disinfection and disinfection by chlorinated disinfectants. (See Drinking Water 'About' section for additional information.) 3 Maximum Contaminant Level (MCL)  Limits set by the EPA for the presence of contaminants in drinking water; an MCL is the highest amount of a substance allowed under the Clean Water Act. The MCL for HAA5 is 60µg/L and consists of 4 seperate potential contaminants. Note: DBP violations occur when the average MCL is exceeded for 4 consecutive quarters. Data Source: Bureau of Water

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Number of Community Water Systems1 (CWS) and Population Served by Max HAA52 Concentrations (micrograms per liter), by Year (2003-2006)
	2003		2004		2005		2006
Concentration in µg/L	Number of CWS	Population Served	Number of CWS	Population Served	Number of CWS	Population Served	Number of CWS	Population Served
Not Sampled	538	1,227,665	291	707,540	430	871,459	429	878,777
<15	1	61,577	220	617,232	99	418,940	96	443,386
15 - <30	5	455,427	22	142,355	17	897,492	22	899,207
30 - <45	5	84,162	33	1,151,325	28	837,762	32	790,263
45 - <60	18	703,655	26	674,703	21	323,024	23	436,268
60 - <753	9	493,872	9	74,705	8	67,276	2	5,980
75+3	23	310,637	2	14,050	3	51,515	3	16,917
1 Community Water System (CWS)   A Community Water System or CWS is defined by the EPA as a public water system that supplies water to the same population year-round.  A public water system is defined as one that provides water for human consumption through a pipe or other constructed conduit to at least fifteen (15) service connectors or serves an average of at least twenty-five (25) people for at least sixty (60) days a year. 2 Halogenic acetic acids (HAA5) are a type of disinfection byproduct that can be found in chlorinated water. Disinfectantion Byproducts (DPB) are chemicals formed when chlorine or other chemicals used to disinfect drinking water sources react with organic (plant or animal) material in the water. These substances are formed during chlorine disinfection and disinfection by chlorinated disinfectants. (See Drinking Water 'About' section for additional information.) 3 Maximum Contaminant Level (MCL)  Limits set by the EPA for the presence of contaminants in drinking water; an MCL is the highest amount of a substance allowed under the Clean Water Act. The MCL for HAA5 is 60µg/L and consists of 4 seperate potential contaminants. Note: DBP violations occur when the average MCL is exceeded for 4 consecutive quarters. Data Source: Bureau of Water

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Number of Community Water Systems1 (CWS) and Population Served by Max HAA52 Concentrations (micrograms per liter), by Year (2007-2010)
	2007		2008		2009		2010
Concentration in µg/L	Number of CWS	Population Served	Number of CWS	Population Served	Number of CWS	Population Served	Number of CWS	Population Served
Not Sampled	445	949,635	427	944,747	439	1,000,176	444	1,080,268
<15	84	793,575	101	776,875	80	389,858	77	732,246
15 - <30	14	177,071	18	590,878	21	898,764	24	840,454
30 - <45	33	780,998	28	838,624	29	698,464	26	705,363
45 - <60	23	726,766	22	276,540	23	585,985	21	364,917
60 - <753	7	143,142	8	179,597	12	210,552	9	96,588
75+3	2	24,208	4	50,319	4	36,800	2	40,259
1 Community Water System (CWS)   A Community Water System or CWS is defined by the EPA as a public water system that supplies water to the same population year-round.  A public water system is defined as one that provides water for human consumption through a pipe or other constructed conduit to at least fifteen (15) service connectors or serves an average of at least twenty-five (25) people for at least sixty (60) days a year. 2 Halogenic acetic acids (HAA5) are a type of disinfection byproduct that can be found in chlorinated water. Disinfectantion Byproducts (DPB) are chemicals formed when chlorine or other chemicals used to disinfect drinking water sources react with organic (plant or animal) material in the water. These substances are formed during chlorine disinfection and disinfection by chlorinated disinfectants. (See Drinking Water 'About' section for additional information.) 3 Maximum Contaminant Level (MCL)  Limits set by the EPA for the presence of contaminants in drinking water; an MCL is the highest amount of a substance allowed under the Clean Water Act. The MCL for HAA5 is 60µg/L and consists of 4 seperate potential contaminants. Note: DBP violations occur when the average MCL is exceeded for 4 consecutive quarters. Data Source: Bureau of Water

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Number of Community Water Systems (CWS) and Population Served by Mean HAA5 Concentrations (micrograms per liter), by Quarter (1999) (2000) (2001) (2002) (2003) (2004) (2005) (2006) (2007) (2008) (2009) (2010)

Number of Community Water Systems1 (CWS) and Population Served by Mean HAA52 Concentrations (micrograms per liter), by Quarter (1999)
	1999
	1st Quarter		2nd Quarter		3rd Quarter		4th Quarter
Concentration in µg/L	Number of CWS	Population Served	Number of CWS	Population Served	Number of CWS	Population Served	Number of CWS	Population Served
Not Sampled	519	1,080,358	516	1,066,188	520	1,132,823	515	1,051,706
<15	14	651,066	14	339,863	14	395,585	18	723,877
15 - <30	17	337,755	6	411,646	8	391,248	8	188,906
30 - <45	16	409,031	19	667,582	9	223,701	25	735,752
45 - <60	13	438,332	12	646,621	9	333,393	8	99,962
60 - <753	7	359,417	13	130,856	16	423,359	6	128,061
75+3	2	28,081	8	41,284	12	403,931	8	375,776
1 Community Water System (CWS)   A Community Water System or CWS is defined by the EPA as a public water system that supplies water to the same population year-round.  A public water system is defined as one that provides water for human consumption through a pipe or other constructed conduit to at least fifteen (15) service connectors or serves an average of at least twenty-five (25) people for at least sixty (60) days a year. 2 Halogenic acetic acids (HAA5) are a type of disinfection byproduct that can be found in chlorinated water. Disinfectantion Byproducts (DPB) are chemicals formed when chlorine or other chemicals used to disinfect drinking water sources react with organic (plant or animal) material in the water. These substances are formed during chlorine disinfection and disinfection by chlorinated disinfectants. (See Drinking Water 'About' section for additional information.) 3 Maximum Contaminant Level (MCL)  Limits set by the EPA for the presence of contaminants in drinking water; an MCL is the highest amount of a substance allowed under the Clean Water Act. The MCL for HAA5 is 60µg/L and consists of 4 seperate potential contaminants. Note: DBP violations occur when the average MCL is exceeded for 4 consecutive quarters. Data Source: Bureau of Water

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Number of Community Water Systems1 (CWS) and Population Served by Mean HAA52 Concentrations (micrograms per liter), by Quarter (2000)
	2000
	1st Quarter		2nd Quarter		3rd Quarter		4th Quarter
Concentration in µg/L	Number of CWS	Population Served	Number of CWS	Population Served	Number of CWS	Population Served	Number of CWS	Population Served
Not Sampled	517	1,067,394	517	1,067,394	517	1,056,197	517	1,056,197
<15	14	695,357	16	399,028	14	699,355	15	699,380
15 - <30	21	826,478	8	202,165	4	32,098	11	361,910
30 - <45	20	580,656	13	899,164	9	371,389	19	548,909
45 - <60	11	83,467	14	553,435	14	462,119	11	525,156
60 - <753	4	45,502	11	126,510	10	447,158	6	35,762
75+3	2	6,392	10	57,550	21	236,930	10	77,932
1 Community Water System (CWS)   A Community Water System or CWS is defined by the EPA as a public water system that supplies water to the same population year-round.  A public water system is defined as one that provides water for human consumption through a pipe or other constructed conduit to at least fifteen (15) service connectors or serves an average of at least twenty-five (25) people for at least sixty (60) days a year. 2 Halogenic acetic acids (HAA5) are a type of disinfection byproduct that can be found in chlorinated water. Disinfectantion Byproducts (DPB) are chemicals formed when chlorine or other chemicals used to disinfect drinking water sources react with organic (plant or animal) material in the water. These substances are formed during chlorine disinfection and disinfection by chlorinated disinfectants. (See Drinking Water 'About' section for additional information.) 3 Maximum Contaminant Level (MCL)  Limits set by the EPA for the presence of contaminants in drinking water; an MCL is the highest amount of a substance allowed under the Clean Water Act. The MCL for HAA5 is 60µg/L and consists of 4 seperate potential contaminants. Note: DBP violations occur when the average MCL is exceeded for 4 consecutive quarters. Data Source: Bureau of Water

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Number of Community Water Systems1 (CWS) and Population Served by Mean HAA52 Concentrations (micrograms per liter), by Quarter (2001)
	2001
	1st Quarter		2nd Quarter		3rd Quarter		4th Quarter
Concentration in µg/L	Number of CWS	Population Served	Number of CWS	Population Served	Number of CWS	Population Served	Number of CWS	Population Served
Not Sampled	517	1,029,773	520	1,065,693	525	1,174,467	516	988,571
<15	15	681,194	10	306,035	8	193,756	12	364,726
15 - <30	19	511,065	9	549,720	3	381,361	9	444,625
30 - <45	21	586,678	16	604,864	10	289,028	15	484,784
45 - <60	12	473,208	10	122,664	15	472,025	19	820,127
60 - <753	2	2,913	6	95,473	10	257,712	11	138,804
75+3	4	20,950	19	561,332	19	537,432	8	64,144
1 Community Water System (CWS)   A Community Water System or CWS is defined by the EPA as a public water system that supplies water to the same population year-round.  A public water system is defined as one that provides water for human consumption through a pipe or other constructed conduit to at least fifteen (15) service connectors or serves an average of at least twenty-five (25) people for at least sixty (60) days a year. 2 Halogenic acetic acids (HAA5) are a type of disinfection byproduct that can be found in chlorinated water. Disinfectantion Byproducts (DPB) are chemicals formed when chlorine or other chemicals used to disinfect drinking water sources react with organic (plant or animal) material in the water. These substances are formed during chlorine disinfection and disinfection by chlorinated disinfectants. (See Drinking Water 'About' section for additional information.) 3 Maximum Contaminant Level (MCL)  Limits set by the EPA for the presence of contaminants in drinking water; an MCL is the highest amount of a substance allowed under the Clean Water Act. The MCL for HAA5 is 60µg/L and consists of 4 seperate potential contaminants. Note: DBP violations occur when the average MCL is exceeded for 4 consecutive quarters. Data Source: Bureau of Water

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Number of Community Water Systems1 (CWS) and Population Served by Mean HAA52 Concentrations (micrograms per liter), by Quarter (2002)
	2002
	1st Quarter		2nd Quarter		3rd Quarter		4th Quarter
Concentration in µg/L	Number of CWS	Population Served	Number of CWS	Population Served	Number of CWS	Population Served	Number of CWS	Population Served
Not Sampled	541	1,314,115	540	1,302,982	541	1,333,847	540	1,318,967
<15	2	114,309	2	114,309	2	114,309	2	64,793
15 - <30	12	616,595	5	395,567	3	331,845	13	961,785
30 - <45	23	972,554	10	396,566	10	263,187	13	627,396
45 - <60	10	253,121	17	867,684	13	591,411	8	83,163
60 - <753	4	51,920	11	129,513	9	461,332	4	85,772
75+3	3	19,402	10	135,395	17	246,085	15	200,140
1 Community Water System (CWS)   A Community Water System or CWS is defined by the EPA as a public water system that supplies water to the same population year-round.  A public water system is defined as one that provides water for human consumption through a pipe or other constructed conduit to at least fifteen (15) service connectors or serves an average of at least twenty-five (25) people for at least sixty (60) days a year. 2 Halogenic acetic acids (HAA5) are a type of disinfection byproduct that can be found in chlorinated water. Disinfectantion Byproducts (DPB) are chemicals formed when chlorine or other chemicals used to disinfect drinking water sources react with organic (plant or animal) material in the water. These substances are formed during chlorine disinfection and disinfection by chlorinated disinfectants. (See Drinking Water 'About' section for additional information.) 3 Maximum Contaminant Level (MCL)  Limits set by the EPA for the presence of contaminants in drinking water; an MCL is the highest amount of a substance allowed under the Clean Water Act. The MCL for HAA5 is 60µg/L and consists of 4 seperate potential contaminants. Note: DBP violations occur when the average MCL is exceeded for 4 consecutive quarters. Data Source: Bureau of Water

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Number of Community Water Systems1 (CWS) and Population Served by Mean HAA52 Concentrations (micrograms per liter), by Quarter (2003)
	2003
	1st Quarter		2nd Quarter		3rd Quarter		4th Quarter
Concentration in µg/L	Number of CWS	Population Served	Number of CWS	Population Served	Number of CWS	Population Served	Number of CWS	Population Served
Not Sampled	539	1,230,780	539	1,252,619	541	1,259,383	538	1,227,665
<15	5	188,347	3	382,561	7	436,685	4	130,870
15 - <30	20	1,038,605	6	193,511	4	178,085	10	549,955
30 - <45	20	419,611	10	182,748	8	389,218	28	899,368
45 - <60	11	435,495	20	1,051,004	13	393,001	10	415,262
60 - <753	2	9,019	6	98,240	12	531,195	7	108,949
75+3	2	15,138	15	176,312	14	149,428	2	4,926
1 Community Water System (CWS)   A Community Water System or CWS is defined by the EPA as a public water system that supplies water to the same population year-round.  A public water system is defined as one that provides water for human consumption through a pipe or other constructed conduit to at least fifteen (15) service connectors or serves an average of at least twenty-five (25) people for at least sixty (60) days a year. 2 Halogenic acetic acids (HAA5) are a type of disinfection byproduct that can be found in chlorinated water. Disinfectantion Byproducts (DPB) are chemicals formed when chlorine or other chemicals used to disinfect drinking water sources react with organic (plant or animal) material in the water. These substances are formed during chlorine disinfection and disinfection by chlorinated disinfectants. (See Drinking Water 'About' section for additional information.) 3 Maximum Contaminant Level (MCL)  Limits set by the EPA for the presence of contaminants in drinking water; an MCL is the highest amount of a substance allowed under the Clean Water Act. The MCL for HAA5 is 60µg/L and consists of 4 seperate potential contaminants. Note: DBP violations occur when the average MCL is exceeded for 4 consecutive quarters. Data Source: Bureau of Water

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Number of Community Water Systems1 (CWS) and Population Served by Mean HAA52 Concentrations (micrograms per liter), by Quarter (2004)
	2004
	1st Quarter		2nd Quarter		3rd Quarter		4th Quarter
Concentration in µg/L	Number of CWS	Population Served	Number of CWS	Population Served	Number of CWS	Population Served	Number of CWS	Population Served
Not Sampled	521	1,019,263	459	853,688	347	786,611	513	966,758
<15	21	738,853	68	482,745	180	567,814	32	1,017,524
15 - <30	36	1,217,716	25	240,322	26	386,013	19	921,604
30 - <45	17	318,491	37	1,269,782	33	1,397,623	20	362,838
45 - <60	7	84,832	9	507,523	14	193,916	13	78,996
60 - <753	1	2,755	4	14,750	3	49,933	5	33,240
75+3	0	0	1	13,100	0	0	1	950
1 Community Water System (CWS)   A Community Water System or CWS is defined by the EPA as a public water system that supplies water to the same population year-round.  A public water system is defined as one that provides water for human consumption through a pipe or other constructed conduit to at least fifteen (15) service connectors or serves an average of at least twenty-five (25) people for at least sixty (60) days a year. 2 Halogenic acetic acids (HAA5) are a type of disinfection byproduct that can be found in chlorinated water. Disinfectantion Byproducts (DPB) are chemicals formed when chlorine or other chemicals used to disinfect drinking water sources react with organic (plant or animal) material in the water. These substances are formed during chlorine disinfection and disinfection by chlorinated disinfectants. (See Drinking Water 'About' section for additional information.) 3 Maximum Contaminant Level (MCL)  Limits set by the EPA for the presence of contaminants in drinking water; an MCL is the highest amount of a substance allowed under the Clean Water Act. The MCL for HAA5 is 60µg/L and consists of 4 seperate potential contaminants. Note: DBP violations occur when the average MCL is exceeded for 4 consecutive quarters. Data Source: Bureau of Water

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Number of Community Water Systems1 (CWS) and Population Served by Mean HAA52 Concentrations (micrograms per liter), by Quarter (2005)
	2005
	1st Quarter		2nd Quarter		3rd Quarter		4th Quarter
Concentration in µg/L	Number of CWS	Population Served	Number of CWS	Population Served	Number of CWS	Population Served	Number of CWS	Population Served
Not Sampled	524	1,117,257	530	1,215,057	433	878,767	528	1,179,833
<15	13	648,749	14	544,752	114	867,473	20	985,857
15 - <30	30	1,037,889	24	996,859	28	762,044	37	936,215
30 - <45	20	364,940	28	587,853	23	860,625	15	335,459
45 - <60	12	212,259	9	108,834	7	91,029	4	19,330
60 - <753	5	42,511	1	14,113	1	7,530	1	3,122
75+3	2	43,863	0	0	0	0	1	7,652
1 Community Water System (CWS)   A Community Water System or CWS is defined by the EPA as a public water system that supplies water to the same population year-round.  A public water system is defined as one that provides water for human consumption through a pipe or other constructed conduit to at least fifteen (15) service connectors or serves an average of at least twenty-five (25) people for at least sixty (60) days a year. 2 Halogenic acetic acids (HAA5) are a type of disinfection byproduct that can be found in chlorinated water. Disinfectantion Byproducts (DPB) are chemicals formed when chlorine or other chemicals used to disinfect drinking water sources react with organic (plant or animal) material in the water. These substances are formed during chlorine disinfection and disinfection by chlorinated disinfectants. (See Drinking Water 'About' section for additional information.) 3 Maximum Contaminant Level (MCL)  Limits set by the EPA for the presence of contaminants in drinking water; an MCL is the highest amount of a substance allowed under the Clean Water Act. The MCL for HAA5 is 60µg/L and consists of 4 seperate potential contaminants. Note: DBP violations occur when the average MCL is exceeded for 4 consecutive quarters. Data Source: Bureau of Water

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Number of Community Water Systems1 (CWS) and Population Served by Mean HAA52 Concentrations (micrograms per liter), by Quarter (2006)
	2006
	1st Quarter		2nd Quarter		3rd Quarter		4th Quarter
Concentration in µg/L	Number of CWS	Population Served	Number of CWS	Population Served	Number of CWS	Population Served	Number of CWS	Population Served
Not Sampled	530	1,227,022	513	1,197,438	445	907,415	529	1,237,385
<15	19	815,595	37	1,168,389	86	429,360	18	606,641
15 - <30	39	1,099,109	40	797,760	26	974,225	22	880,136
30 - <45	14	290,473	15	294,838	31	785,524	30	666,986
45 - <60	3	26,177	2	12,373	16	363,799	7	76,895
60 - <753	1	5,912	0	0	1	68	1	2,755
75+3	1	6,510	0	0	2	10,407	0	0
1 Community Water System (CWS)   A Community Water System or CWS is defined by the EPA as a public water system that supplies water to the same population year-round.  A public water system is defined as one that provides water for human consumption through a pipe or other constructed conduit to at least fifteen (15) service connectors or serves an average of at least twenty-five (25) people for at least sixty (60) days a year. 2 Halogenic acetic acids (HAA5) are a type of disinfection byproduct that can be found in chlorinated water. Disinfectantion Byproducts (DPB) are chemicals formed when chlorine or other chemicals used to disinfect drinking water sources react with organic (plant or animal) material in the water. These substances are formed during chlorine disinfection and disinfection by chlorinated disinfectants. (See Drinking Water 'About' section for additional information.) 3 Maximum Contaminant Level (MCL)  Limits set by the EPA for the presence of contaminants in drinking water; an MCL is the highest amount of a substance allowed under the Clean Water Act. The MCL for HAA5 is 60µg/L and consists of 4 seperate potential contaminants. Note: DBP violations occur when the average MCL is exceeded for 4 consecutive quarters. Data Source: Bureau of Water

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Number of Community Water Systems1 (CWS) and Population Served by Mean HAA52 Concentrations (micrograms per liter), by Quarter (2007)
	2007
	1st Quarter		2nd Quarter		3rd Quarter		4th Quarter
Concentration in µg/L	Number of CWS	Population Served	Number of CWS	Population Served	Number of CWS	Population Served	Number of CWS	Population Served
Not Sampled	530	1,252,663	497	1,213,877	481	1,019,032	529	1,260,681
<15	10	728,900	46	586,291	56	771,804	12	644,944
15 - <30	26	492,451	15	629,769	33	910,726	23	477,833
30 - <45	35	966,607	30	722,496	22	443,557	34	1,124,553
45 - <60	3	94,931	16	345,131	14	441,023	10	87,384
60 - <753	3	38,390	3	95,076	2	9,253	0	0
75+3	1	21,453	1	2,755	0	0	0	0
1 Community Water System (CWS)   A Community Water System or CWS is defined by the EPA as a public water system that supplies water to the same population year-round.  A public water system is defined as one that provides water for human consumption through a pipe or other constructed conduit to at least fifteen (15) service connectors or serves an average of at least twenty-five (25) people for at least sixty (60) days a year. 2 Halogenic acetic acids (HAA5) are a type of disinfection byproduct that can be found in chlorinated water. Disinfectantion Byproducts (DPB) are chemicals formed when chlorine or other chemicals used to disinfect drinking water sources react with organic (plant or animal) material in the water. These substances are formed during chlorine disinfection and disinfection by chlorinated disinfectants. (See Drinking Water 'About' section for additional information.) 3 Maximum Contaminant Level (MCL)  Limits set by the EPA for the presence of contaminants in drinking water; an MCL is the highest amount of a substance allowed under the Clean Water Act. The MCL for HAA5 is 60µg/L and consists of 4 seperate potential contaminants. Note: DBP violations occur when the average MCL is exceeded for 4 consecutive quarters. Data Source: Bureau of Water

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Number of Community Water Systems1 (CWS) and Population Served by Mean HAA52 Concentrations (micrograms per liter), by Quarter (2008)
	2008
	1st Quarter		2nd Quarter		3rd Quarter		4th Quarter
Concentration in µg/L	Number of CWS	Population Served	Number of CWS	Population Served	Number of CWS	Population Served	Number of CWS	Population Served
Not Sampled	529	1,291,742	481	1,121,804	475	1,117,169	529	1,291,742
<15	16	820,066	55	611,528	60	732,050	16	679,539
15 - <30	32	837,473	24	879,394	25	760,132	25	876,762
30 - <45	25	631,628	32	879,107	29	748,829	26	680,275
45 - <60	3	43,075	15	152,697	12	125,742	10	116,895
60 - <753	1	2,755	1	13,050	5	154,180	2	12,367
75+3	2	30,841	0	0	2	19,478	0	0
1 Community Water System (CWS)   A Community Water System or CWS is defined by the EPA as a public water system that supplies water to the same population year-round.  A public water system is defined as one that provides water for human consumption through a pipe or other constructed conduit to at least fifteen (15) service connectors or serves an average of at least twenty-five (25) people for at least sixty (60) days a year. 2 Halogenic acetic acids (HAA5) are a type of disinfection byproduct that can be found in chlorinated water. Disinfectantion Byproducts (DPB) are chemicals formed when chlorine or other chemicals used to disinfect drinking water sources react with organic (plant or animal) material in the water. These substances are formed during chlorine disinfection and disinfection by chlorinated disinfectants. (See Drinking Water 'About' section for additional information.) 3 Maximum Contaminant Level (MCL)  Limits set by the EPA for the presence of contaminants in drinking water; an MCL is the highest amount of a substance allowed under the Clean Water Act. The MCL for HAA5 is 60µg/L and consists of 4 seperate potential contaminants. Note: DBP violations occur when the average MCL is exceeded for 4 consecutive quarters. Data Source: Bureau of Water

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Number of Community Water Systems1 (CWS) and Population Served by Mean HAA52 Concentrations (micrograms per liter), by Quarter (2009)
	2009
	1st Quarter		2nd Quarter		3rd Quarter		4th Quarter
Concentration in µg/L	Number of CWS	Population Served	Number of CWS	Population Served	Number of CWS	Population Served	Number of CWS	Population Served
Not Sampled	529	1,673,507	499	1,194,607	468	1,177,576	529	1,374,167
<15	10	435,278	35	531,359	69	709,901	12	782,893
15 - <30	18	784,855	21	820,480	34	1,089,467	35	856,493
30 - <45	22	473,073	31	929,191	23	405,869	28	771,742
45 - <60	18	259,185	18	283,016	11	435,153	2	35,211
60 - <753	10	188,810	2	31,105	2	2,565	2	93
75+3	1	5,891	2	30,841	1	68	0	0
1 Community Water System (CWS)   A Community Water System or CWS is defined by the EPA as a public water system that supplies water to the same population year-round.  A public water system is defined as one that provides water for human consumption through a pipe or other constructed conduit to at least fifteen (15) service connectors or serves an average of at least twenty-five (25) people for at least sixty (60) days a year. 2 Halogenic acetic acids (HAA5) are a type of disinfection byproduct that can be found in chlorinated water. Disinfectantion Byproducts (DPB) are chemicals formed when chlorine or other chemicals used to disinfect drinking water sources react with organic (plant or animal) material in the water. These substances are formed during chlorine disinfection and disinfection by chlorinated disinfectants. (See Drinking Water 'About' section for additional information.) 3 Maximum Contaminant Level (MCL)  Limits set by the EPA for the presence of contaminants in drinking water; an MCL is the highest amount of a substance allowed under the Clean Water Act. The MCL for HAA5 is 60µg/L and consists of 4 seperate potential contaminants. Note: DBP violations occur when the average MCL is exceeded for 4 consecutive quarters. Data Source: Bureau of Water

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Number of Community Water Systems1 (CWS) and Population Served by Mean HAA52 Concentrations (micrograms per liter), by Quarter (2010)
	2010
	1st Quarter		2nd Quarter		3rd Quarter		4th Quarter
Concentration in µg/L	Number of CWS	Population Served	Number of CWS	Population Served	Number of CWS	Population Served	Number of CWS	Population Served
Not Sampled	524	1,403,050	510	1,284,852	459	1,202,068	525	1,403,559
<15	7	680,397	22	803,940	83	839,130	18	623,871
15 - <30	28	840,713	28	738,412	32	1,028,976	37	1,560,239
30 - <45	25	627,517	20	621,216	20	677,446	18	249,451
45 - <60	16	264,290	14	295,902	9	112,475	3	7,677
60 - <753	3	44,128	7	75,514	0	0	2	15,298
75+3	0	0	2	40,259	0	0	0	0
1 Community Water System (CWS)   A Community Water System or CWS is defined by the EPA as a public water system that supplies water to the same population year-round.  A public water system is defined as one that provides water for human consumption through a pipe or other constructed conduit to at least fifteen (15) service connectors or serves an average of at least twenty-five (25) people for at least sixty (60) days a year. 2 Halogenic acetic acids (HAA5) are a type of disinfection byproduct that can be found in chlorinated water. Disinfectantion Byproducts (DPB) are chemicals formed when chlorine or other chemicals used to disinfect drinking water sources react with organic (plant or animal) material in the water. These substances are formed during chlorine disinfection and disinfection by chlorinated disinfectants. (See Drinking Water 'About' section for additional information.) 3 Maximum Contaminant Level (MCL)  Limits set by the EPA for the presence of contaminants in drinking water; an MCL is the highest amount of a substance allowed under the Clean Water Act. The MCL for HAA5 is 60µg/L and consists of 4 seperate potential contaminants. Note: DBP violations occur when the average MCL is exceeded for 4 consecutive quarters. Data Source: Bureau of Water

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Nitrate Data

Number of Community Water Systems (CWS) and Population Served by Mean Nitrate Concentrations (milligrams per liter), by Year (1999-2002) (2003-2006) (2007-2010)

Number of Community Water Systems1 (CWS) and Population Served by Mean Nitrate Concentrations (milligrams per liter), by Year (1999-2002)
	1999		2000		2001		2002
Concentration in mg/L	Number of CWS	Population Served	Number of CWS	Population Served	Number of CWS	Population Served	Number of CWS	Population Served
Not Sampled	192	827,138	153	808,963	235	1,242,810	152	801,747
<3	390	2,474,172	426	2,491,039	347	2,058,074	429	2,533,327
3 - <5	3	228	10	5,244	7	4,737	10	4,818
5 - <10	3	2,502	0	0	1	160	4	2,124
10+2	0	0	0	0	0	0	0	0
1 Community Water System (CWS)   A Community Water System or CWS is defined by the EPA as a public water system that supplies water to the same population year-round.  A public water system is defined as one that provides water for human consumption through a pipe or other constructed conduit to at least fifteen (15) service connectors or serves an average of at least twenty-five (25) people for at least sixty (60) days a year. 2 Maximum Contaminant Level (MCL)  Limits set by the EPA for the presence of contaminants in drinking water; an MCL is the highest amount of a substance allowed under the Clean Water Act. The MCL for Nitrate is 10mg/L. Data Source: Bureau of Water

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Number of Community Water Systems1 (CWS) and Population Served by Mean Nitrate Concentrations (milligrams per liter), by Year (2003-2006)
	2003		2004		2005		2006
Concentration in mg/L	Number of CWS	Population Served	Number of CWS	Population Served	Number of CWS	Population Served	Number of CWS	Population Served
Not Sampled	147	803,319	169	955,660	184	1,013,744	158	913,183
<3	438	2,516,376	424	2,421,821	405	2,444,530	442	2,555,038
3 - <5	11	14,657	9	4,269	16	9,034	6	2,417
5 - <10	3	2,643	1	160	1	160	1	160
10+2	0	0	0	0	0	0	0	0
1 Community Water System (CWS)   A Community Water System or CWS is defined by the EPA as a public water system that supplies water to the same population year-round.  A public water system is defined as one that provides water for human consumption through a pipe or other constructed conduit to at least fifteen (15) service connectors or serves an average of at least twenty-five (25) people for at least sixty (60) days a year. 2 Maximum Contaminant Level (MCL)  Limits set by the EPA for the presence of contaminants in drinking water; an MCL is the highest amount of a substance allowed under the Clean Water Act. The MCL for Nitrate is 10mg/L. Data Source: Bureau of Water

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Number of Community Water Systems1 (CWS) and Population Served by Mean Nitrate Concentrations (milligrams per liter), by Year (2007-2010)
	2007		2008		2009		2010
Concentration in mg/L	Number of CWS	Population Served	Number of CWS	Population Served	Number of CWS	Population Served	Number of CWS	Population Served
Not Sampled	239	1,702,318	147	948,272	150	1,049,787	150	1,044,403
<3	359	1,886,780	446	2,698,114	449	2,764,997	436	2,808,699
3 - <5	9	6,137	14	11,110	7	3,098	12	6,217
5 - <10	1	160	1	84	2	2,717	5	776
10+2	0	0	0	0	0	0	0	0
1 Community Water System (CWS)   A Community Water System or CWS is defined by the EPA as a public water system that supplies water to the same population year-round.  A public water system is defined as one that provides water for human consumption through a pipe or other constructed conduit to at least fifteen (15) service connectors or serves an average of at least twenty-five (25) people for at least sixty (60) days a year. 2 Maximum Contaminant Level (MCL)  Limits set by the EPA for the presence of contaminants in drinking water; an MCL is the highest amount of a substance allowed under the Clean Water Act. The MCL for Nitrate is 10mg/L. Data Source: Bureau of Water

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Number of Community Water Systems (CWS) and Population Served by Max Nitrate Concentrations (milligrams per liter), by Year (1999-2002) (2003-2006) (2007-2010)

Number of Community Water Systems1 (CWS) and Population Served by Max Nitrate Concentrations (milligrams per liter), by Year (1999-2002)
	1999		2000		2001		2002
Concentration in mg/L	Number of CWS	Population Served	Number of CWS	Population Served	Number of CWS	Population Served	Number of CWS	Population Served
Not Sampled	192	827,138	153	808,963	235	1,242,810	152	801,747
<3	389	2,472,825	426	2,491,039	346	2,057,994	428	2,531,980
3 - <5	4	1,575	9	2,941	6	2,314	9	3,662
5 - <10	3	2,502	1	2,303	3	2,663	6	4,627
10+2	0	0	0	0	0	0	0	0
1 Community Water System (CWS)   A Community Water System or CWS is defined by the EPA as a public water system that supplies water to the same population year-round.  A public water system is defined as one that provides water for human consumption through a pipe or other constructed conduit to at least fifteen (15) service connectors or serves an average of at least twenty-five (25) people for at least sixty (60) days a year. 2 Maximum Contaminant Level (MCL)  Limits set by the EPA for the presence of contaminants in drinking water; an MCL is the highest amount of a substance allowed under the Clean Water Act. The MCL for Nitrate is 10mg/L. Data Source: Bureau of Water

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Number of Community Water Systems1 (CWS) and Population Served by Max Nitrate Concentrations (milligrams per liter), by Year (2003-2006)
	2003		2004		2005		2006
Concentration in mg/L	Number of CWS	Population Served	Number of CWS	Population Served	Number of CWS	Population Served	Number of CWS	Population Served
Not Sampled	147	803,319	169	955,660	184	1,013,744	158	913,183
<3	436	2,516,067	422	2,410,199	404	2,444,330	438	2,548,545
3 - <5	12	4,105	10	13,588	16	9,034	9	8,642
5 - <10	4	13,504	2	2,463	2	360	2	428
10+2	0	0	0	0	0	0	0	0
1 Community Water System (CWS)   A Community Water System or CWS is defined by the EPA as a public water system that supplies water to the same population year-round.  A public water system is defined as one that provides water for human consumption through a pipe or other constructed conduit to at least fifteen (15) service connectors or serves an average of at least twenty-five (25) people for at least sixty (60) days a year. 2 Maximum Contaminant Level (MCL)  Limits set by the EPA for the presence of contaminants in drinking water; an MCL is the highest amount of a substance allowed under the Clean Water Act. The MCL for Nitrate is 10mg/L. Data Source: Bureau of Water

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Number of Community Water Systems1 (CWS) and Population Served by Max Nitrate Concentrations (milligrams per liter), by Year (2007-2010)
	2007		2008		2009		2010
Concentration in mg/L	Number of CWS	Population Served	Number of CWS	Population Served	Number of CWS	Population Served	Number of CWS	Population Served
Not Sampled	239	1,702,318	147	948,272	150	1,049,787	150	1,044,403
<3	358	1,886,512	444	2,688,526	445	2,763,171	422	2,737,587
3 - <5	8	6,053	11	8,165	7	4,337	24	74,383
5 - <10	2	352	6	12,617	6	3,304	5	3,422
10+2	1	160	0	0	0	0	2	300
1 Community Water System (CWS)   A Community Water System or CWS is defined by the EPA as a public water system that supplies water to the same population year-round.  A public water system is defined as one that provides water for human consumption through a pipe or other constructed conduit to at least fifteen (15) service connectors or serves an average of at least twenty-five (25) people for at least sixty (60) days a year. 2 Maximum Contaminant Level (MCL)  Limits set by the EPA for the presence of contaminants in drinking water; an MCL is the highest amount of a substance allowed under the Clean Water Act. The MCL for Nitrate is 10mg/L. Data Source: Bureau of Water

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Number of Community Water Systems (CWS) and Population Served by Mean Nitrate Concentrations (milligrams per liter), by Quarter (1999) (2000) (2001) (2002) (2003) (2004) (2005) (2006) (2007) (2008) (2009) (2010)

Number of Community Water Systems1 (CWS) and Population Served by Mean Nitrate Concentrations (milligrams per liter), by Quarter (1999)
	1999
	1st Quarter		2nd Quarter		3rd Quarter		4th Quarter
Concentration in mg/L	Number of CWS	Population Served	Number of CWS	Population Served	Number of CWS	Population Served	Number of CWS	Population Served
Not Sampled	475	1,077,456	457	3,178,249	448	3,246,543	540	3,090,700
<3	112	2,226,558	128	124,210	136	54,847	47	213,160
3 - <5	1	26	2	1,401	1	148	0	0
5 - <10	0	0	1	180	3	2,502	1	180
10+2	0	0	0	0	0	0	0	0
1 Community Water System (CWS)   A Community Water System or CWS is defined by the EPA as a public water system that supplies water to the same population year-round.  A public water system is defined as one that provides water for human consumption through a pipe or other constructed conduit to at least fifteen (15) service connectors or serves an average of at least twenty-five (25) people for at least sixty (60) days a year. 2 Maximum Contaminant Level (MCL)  Limits set by the EPA for the presence of contaminants in drinking water; an MCL is the highest amount of a substance allowed under the Clean Water Act. The MCL for Nitrate is 10mg/L. Data Source: Bureau of Water

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Number of Community Water Systems1 (CWS) and Population Served by Mean Nitrate Concentrations (milligrams per liter), by Quarter (2000)
	2000
	1st Quarter		2nd Quarter		3rd Quarter		4th Quarter
Concentration in mg/L	Number of CWS	Population Served	Number of CWS	Population Served	Number of CWS	Population Served	Number of CWS	Population Served
Not Sampled	449	2,825,555	415	1,776,609	485	2,818,041	513	2,964,590
<3	137	478,731	171	1,528,229	103	487,179	73	336,806
3 - <5	3	960	3	408	1	26	2	1,547
5 - <10	0	0	0	0	0	0	1	2,303
10+2	0	0	0	0	0	0	0	0
1 Community Water System (CWS)   A Community Water System or CWS is defined by the EPA as a public water system that supplies water to the same population year-round.  A public water system is defined as one that provides water for human consumption through a pipe or other constructed conduit to at least fifteen (15) service connectors or serves an average of at least twenty-five (25) people for at least sixty (60) days a year. 2 Maximum Contaminant Level (MCL)  Limits set by the EPA for the presence of contaminants in drinking water; an MCL is the highest amount of a substance allowed under the Clean Water Act. The MCL for Nitrate is 10mg/L. Data Source: Bureau of Water

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Number of Community Water Systems1 (CWS) and Population Served by Mean Nitrate Concentrations (milligrams per liter), by Quarter (2001)
	2001
	1st Quarter		2nd Quarter		3rd Quarter		4th Quarter
Concentration in mg/L	Number of CWS	Population Served	Number of CWS	Population Served	Number of CWS	Population Served	Number of CWS	Population Served
Not Sampled	469	1,481,817	511	3,193,818	487	3,182,608	498	3,083,424
<3	118	1,820,741	77	110,623	98	120,336	90	222,251
3 - <5	1	720	2	1,340	3	374	2	106
5 - <10	2	2,503	0	0	2	2,463	0	0
10+2	0	0	0	0	0	0	0	0
1 Community Water System (CWS)   A Community Water System or CWS is defined by the EPA as a public water system that supplies water to the same population year-round.  A public water system is defined as one that provides water for human consumption through a pipe or other constructed conduit to at least fifteen (15) service connectors or serves an average of at least twenty-five (25) people for at least sixty (60) days a year. 2 Maximum Contaminant Level (MCL)  Limits set by the EPA for the presence of contaminants in drinking water; an MCL is the highest amount of a substance allowed under the Clean Water Act. The MCL for Nitrate is 10mg/L. Data Source: Bureau of Water

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Number of Community Water Systems1 (CWS) and Population Served by Mean Nitrate Concentrations (milligrams per liter), by Quarter (2002)
	2002
	1st Quarter		2nd Quarter		3rd Quarter		4th Quarter
Concentration in mg/L	Number of CWS	Population Served	Number of CWS	Population Served	Number of CWS	Population Served	Number of CWS	Population Served
Not Sampled	471	1,861,285	423	2,445,597	526	3,233,492	469	3,010,185
<3	121	1,476,981	164	892,752	66	105,946	120	329,327
3 - <5	2	1,447	7	3,507	2	275	1	180
5 - <10	1	2,303	1	160	1	2,303	5	2,324
10+2	0	0	0	0	0	0	0	0
1 Community Water System (CWS)   A Community Water System or CWS is defined by the EPA as a public water system that supplies water to the same population year-round.  A public water system is defined as one that provides water for human consumption through a pipe or other constructed conduit to at least fifteen (15) service connectors or serves an average of at least twenty-five (25) people for at least sixty (60) days a year. 2 Maximum Contaminant Level (MCL)  Limits set by the EPA for the presence of contaminants in drinking water; an MCL is the highest amount of a substance allowed under the Clean Water Act. The MCL for Nitrate is 10mg/L. Data Source: Bureau of Water

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Number of Community Water Systems1 (CWS) and Population Served by Mean Nitrate Concentrations (milligrams per liter), by Quarter (2003)
	2003
	1st Quarter		2nd Quarter		3rd Quarter		4th Quarter
Concentration in mg/L	Number of CWS	Population Served	Number of CWS	Population Served	Number of CWS	Population Served	Number of CWS	Population Served
Not Sampled	463	1,177,610	460	3,029,014	468	3,188,857	507	3,227,467
<3	130	2,154,319	131	293,364	125	146,455	87	97,558
3 - <5	5	4,906	4	1,113	4	1,343	3	929
5 - <10	1	160	4	13,504	2	340	2	11,041
10+2	0	0	0	0	0	0	0	0
1 Community Water System (CWS)   A Community Water System or CWS is defined by the EPA as a public water system that supplies water to the same population year-round.  A public water system is defined as one that provides water for human consumption through a pipe or other constructed conduit to at least fifteen (15) service connectors or serves an average of at least twenty-five (25) people for at least sixty (60) days a year. 2 Maximum Contaminant Level (MCL)  Limits set by the EPA for the presence of contaminants in drinking water; an MCL is the highest amount of a substance allowed under the Clean Water Act. The MCL for Nitrate is 10mg/L. Data Source: Bureau of Water

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Number of Community Water Systems1 (CWS) and Population Served by Mean Nitrate Concentrations (milligrams per liter), by Quarter (2004)
	2004
	1st Quarter		2nd Quarter		3rd Quarter		4th Quarter
Concentration in mg/L	Number of CWS	Population Served	Number of CWS	Population Served	Number of CWS	Population Served	Number of CWS	Population Served
Not Sampled	474	1,810,572	506	2,647,548	436	3,061,375	511	3,138,993
<3	125	1,558,416	93	733,842	165	318,072	88	242,451
3 - <5	4	12,922	3	360	0	0	3	306
5 - <10	0	0	1	160	2	2,463	1	160
10+2	0	0	0	0	0	0	0	0
1 Community Water System (CWS)   A Community Water System or CWS is defined by the EPA as a public water system that supplies water to the same population year-round.  A public water system is defined as one that provides water for human consumption through a pipe or other constructed conduit to at least fifteen (15) service connectors or serves an average of at least twenty-five (25) people for at least sixty (60) days a year. 2 Maximum Contaminant Level (MCL)  Limits set by the EPA for the presence of contaminants in drinking water; an MCL is the highest amount of a substance allowed under the Clean Water Act. The MCL for Nitrate is 10mg/L. Data Source: Bureau of Water

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Number of Community Water Systems1 (CWS) and Population Served by Mean Nitrate Concentrations (milligrams per liter), by Quarter (2005)
	2005
	1st Quarter		2nd Quarter		3rd Quarter		4th Quarter
Concentration in mg/L	Number of CWS	Population Served	Number of CWS	Population Served	Number of CWS	Population Served	Number of CWS	Population Served
Not Sampled	501	2,769,142	482	2,677,118	510	3,172,376	485	2,662,272
<3	102	694,951	117	786,995	91	293,384	114	803,520
3 - <5	3	3,375	5	2,995	4	1,548	5	1,316
5 - <10	0	0	2	360	1	160	2	360
10+2	0	0	0	0	0	0	0	0
1 Community Water System (CWS)   A Community Water System or CWS is defined by the EPA as a public water system that supplies water to the same population year-round.  A public water system is defined as one that provides water for human consumption through a pipe or other constructed conduit to at least fifteen (15) service connectors or serves an average of at least twenty-five (25) people for at least sixty (60) days a year. 2 Maximum Contaminant Level (MCL)  Limits set by the EPA for the presence of contaminants in drinking water; an MCL is the highest amount of a substance allowed under the Clean Water Act. The MCL for Nitrate is 10mg/L. Data Source: Bureau of Water

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Number of Community Water Systems1 (CWS) and Population Served by Mean Nitrate Concentrations (milligrams per liter), by Quarter (2006)
	2006
	1st Quarter		2nd Quarter		3rd Quarter		4th Quarter
Concentration in mg/L	Number of CWS	Population Served	Number of CWS	Population Served	Number of CWS	Population Served	Number of CWS	Population Served
Not Sampled	455	1,970,045	489	2,934,593	504	3,190,585	490	2,847,537
<3	148	1,499,406	112	533,431	99	274,909	115	622,001
3 - <5	3	1,187	5	2,614	3	5,036	2	1,260
5 - <10	1	160	1	160	1	268	0	0
10+2	0	0	0	0	0	0	0	0
1 Community Water System (CWS)   A Community Water System or CWS is defined by the EPA as a public water system that supplies water to the same population year-round.  A public water system is defined as one that provides water for human consumption through a pipe or other constructed conduit to at least fifteen (15) service connectors or serves an average of at least twenty-five (25) people for at least sixty (60) days a year. 2 Maximum Contaminant Level (MCL)  Limits set by the EPA for the presence of contaminants in drinking water; an MCL is the highest amount of a substance allowed under the Clean Water Act. The MCL for Nitrate is 10mg/L. Data Source: Bureau of Water

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Number of Community Water Systems1 (CWS) and Population Served by Mean Nitrate Concentrations (milligrams per liter), by Quarter (2007)
	2007
	1st Quarter		2nd Quarter		3rd Quarter		4th Quarter
Concentration in mg/L	Number of CWS	Population Served	Number of CWS	Population Served	Number of CWS	Population Served	Number of CWS	Population Served
Not Sampled	501	3,186,342	521	3,059,055	438	2,793,391	570	3,235,497
<3	101	407,002	82	534,401	166	798,573	35	359,386
3 - <5	4	1,623	3	1,511	2	3,003	0	0
5 - <10	2	428	1	268	2	428	3	512
10+2	0	0	1	160	0	0	0	0
1 Community Water System (CWS)   A Community Water System or CWS is defined by the EPA as a public water system that supplies water to the same population year-round.  A public water system is defined as one that provides water for human consumption through a pipe or other constructed conduit to at least fifteen (15) service connectors or serves an average of at least twenty-five (25) people for at least sixty (60) days a year. 2 Maximum Contaminant Level (MCL)  Limits set by the EPA for the presence of contaminants in drinking water; an MCL is the highest amount of a substance allowed under the Clean Water Act. The MCL for Nitrate is 10mg/L. Data Source: Bureau of Water

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Number of Community Water Systems1 (CWS) and Population Served by Mean Nitrate Concentrations (milligrams per liter), by Quarter (2008)
	2008
	1st Quarter		2nd Quarter		3rd Quarter		4th Quarter
Concentration in mg/L	Number of CWS	Population Served	Number of CWS	Population Served	Number of CWS	Population Served	Number of CWS	Population Served
Not Sampled	467	2,158,715	471	2,530,530	432	3,184,354	561	3,323,724
<3	131	1,481,859	134	1,124,181	167	466,646	42	333,119
3 - <5	6	7,106	0	0	6	3,635	1	25
5 - <10	4	9,900	3	2,869	3	2,945	4	712
10+2	0	0	0	0	0	0	0	0
1 Community Water System (CWS)   A Community Water System or CWS is defined by the EPA as a public water system that supplies water to the same population year-round.  A public water system is defined as one that provides water for human consumption through a pipe or other constructed conduit to at least fifteen (15) service connectors or serves an average of at least twenty-five (25) people for at least sixty (60) days a year. 2 Maximum Contaminant Level (MCL)  Limits set by the EPA for the presence of contaminants in drinking water; an MCL is the highest amount of a substance allowed under the Clean Water Act. The MCL for Nitrate is 10mg/L. Data Source: Bureau of Water

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Number of Community Water Systems1 (CWS) and Population Served by Mean Nitrate Concentrations (milligrams per liter), by Quarter (2009)
	2009
	1st Quarter		2nd Quarter		3rd Quarter		4th Quarter
Concentration in mg/L	Number of CWS	Population Served	Number of CWS	Population Served	Number of CWS	Population Served	Number of CWS	Population Served
Not Sampled	466	2,275,170	467	2,958,279	436	3,319,613	541	3,575,918
<3	135	1,540,726	132	857,366	165	498,939	59	241,048
3 - <5	2	1,547	4	1,661	2	1,400	3	340
5 - <10	5	3,156	5	3,293	5	647	5	3,293
10+2	0	0	0	0	0	0	0	0
1 Community Water System (CWS)   A Community Water System or CWS is defined by the EPA as a public water system that supplies water to the same population year-round.  A public water system is defined as one that provides water for human consumption through a pipe or other constructed conduit to at least fifteen (15) service connectors or serves an average of at least twenty-five (25) people for at least sixty (60) days a year. 2 Maximum Contaminant Level (MCL)  Limits set by the EPA for the presence of contaminants in drinking water; an MCL is the highest amount of a substance allowed under the Clean Water Act. The MCL for Nitrate is 10mg/L. Data Source: Bureau of Water

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Number of Community Water Systems1 (CWS) and Population Served by Mean Nitrate Concentrations (milligrams per liter), by Quarter (2010)
	2010
	1st Quarter		2nd Quarter		3rd Quarter		4th Quarter
Concentration in mg/L	Number of CWS	Population Served	Number of CWS	Population Served	Number of CWS	Population Served	Number of CWS	Population Served
Not Sampled	465	2,306,096	467	2,899,369	441	3,446,805	529	3,525,013
<3	128	1,547,469	129	956,523	153	407,506	63	330,808
3 - <5	6	3,357	2	918	4	5,008	7	1,080
5 - <10	4	3,173	5	3,285	5	776	4	3,194
10+2	0	0	0	0	0	0	0	0
1 Community Water System (CWS)   A Community Water System or CWS is defined by the EPA as a public water system that supplies water to the same population year-round.  A public water system is defined as one that provides water for human consumption through a pipe or other constructed conduit to at least fifteen (15) service connectors or serves an average of at least twenty-five (25) people for at least sixty (60) days a year. 2 Maximum Contaminant Level (MCL)  Limits set by the EPA for the presence of contaminants in drinking water; an MCL is the highest amount of a substance allowed under the Clean Water Act. The MCL for Nitrate is 10mg/L. Data Source: Bureau of Water

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