Drinking Water


Environmental Protection Agency (EPA)

Key information

The number of tests carried out on drinking water supplies; compliance with drinking water standards by water supply category and test parameter; the number of water supplies by supply category and the proportion of the population served; the number of water supplies on, added to or removed from the EPA remedial action list; the number of water supplies with issues identified by EPA audits classified by audit issue. Information is supplied, classified by individual county councils, for monitoring, overall compliance, compliance with the E. coli standard and chemical and indicator parametric values, and EPA enforcement actions.


Data supplied by local authorities and the National Federation of Group Water Schemes and EPA administrative records.


Public water supplies, public group water schemes, private group water schemes and small private supplies.



Reference period

Calendar year

Start date



16 months (monitoring), 7 months (enforcement) from the end of the reference period


  • Water supply category
    Public water supplies; Public group water schemes; Private group water schemes; Small private supplies.
  • Test parameter
    Microbiological (E. coli; Enterococci); Chemical (1,2-dichloroethane; Antimony; Arsenic; Benzene; Benzo(a)pyrene; Boron; Bromate; Cadmium; Chromium; Copper; Cyanide; Fluoride; Lead; Mercury; Nickel; Nitrate; Nitrite (at tap); Nitrites (at WTW); PAH; Pesticides, total; Selenium; Tetrachloroethene & trichloroethene; Trihalomethanes, total); Indicator (Aluminium; Ammonium; Chloride; Clostridium Perfringens; Coliform Bacteria; Colony count @ 22C; Colour; Conductivity; Iron; Manganese; Odour; Oxidisability; pH; Sodium; Sulphate; Taste; Total organic carbon; Turbidity (at tap); Turbidity (at WTW)); Radioactivity (Tritium; Total indicative dose).
  • Audit issues
    Problems in the operation of the filters; No turbidity monitors on each filter; Inadequate chemical dosing arrangements; No chlorine monitor and alarm; Floc carryover from the clarifier; No source-protection measures in place; Final water turbidity >1.0 NTU; No duty and standby chlorine pumps; Plant operating >10% above design capacity; Inadequate disinfection contact time; Treatment process partially or fully bypassed; Unapproved/inappropriate chemicals used; Uncovered reservoir/contact tank.
  • County
    The 34 administrative counties - Water Service Authorities.


Environment, Climate and Energy - Environment

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