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Drinking Water Compliance Monitoring

Tier 1 Public Notice - Required Within 24 Hours

  • Fecal coliform maximum contaminant level (MCL) violation or failure to test for fecal contamination after total coliform test is positive
  • Nitrate/nitrite/combined nitrate and nitrite MCL violation or failure to take confirmation sample
  • Chlorine dioxide maximum residual distribution level (MRDL) violation in distribution system or failure to take repeat samples in distribution system
  • Exceedance of maximum allowable turbidity level resulting in an MCL or treatment technique (TT) violation, when the State or EPA determines a Tier 1 notice is warranted
  • Special public notice for non-community water systems with nitrate exceedances between 10 mg/l and 20 mg/l, when allowed to exceed MCL (10 mg/l) by the State
  • Waterborne disease outbreak or other waterborne emergency
  • Other situations as determined by the primacy agency

Tier 2 Public Notice - Required Within 30 Days

  • All other MCL, MRDL, and TT violations not identified as a Tier 1 notice
  • Monitoring and testing procedure violations, when the primacy agency requires a Tier 2 (rather than Tier 3) notice
  • Failure to comply with variance and exemption (V&E) conditions

Tier 3 Public Notice - Required Within 1 Year

  • All other monitoring or testing procedure violations not already requiring a Tier 1 or Tier 2 notice
  • Operation under a V & E
  • Special public notices (i.e., exceedance of the fluoride secondary maximum contaminant level (SMCL); announcing the availability of unregulated contaminant monitoring results)


Bureau of Water . Phone: (803) 898-4300 . Fax: (803) 898-3795 . Contact Us