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Drinking Water Quality

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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

Directions: In order to view data tables, you must click on the year of interest. Once the table is open for viewing, you can close the table by clicking on the year again.

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


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


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


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


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


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


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


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


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


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


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


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


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


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


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


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


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


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


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


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


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


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


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


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


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


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


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


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


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


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


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


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


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


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


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


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


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


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


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


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


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


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


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


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


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


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


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


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


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


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


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


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


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


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


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


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


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


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


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


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


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


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


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


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


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


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


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


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


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


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


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


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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