Water Quality
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Types of Drinking Water Contaminants

Drinking water contaminants may be classified as inorganic compounds, organic compounds, disinfection byproducts, radionuclides, or infectious agents. Tracking California provides data for certain contaminants of concern, listed below. Each contaminant is monitored and regulated against standards such as a maximum contaminant level (MCL) or a required treatment technique (TT) established by the US Environmental Protections Agency (EPA).

For a complete list of primary drinking water contaminants and their regulatory limits and health effects, see the EPA's National Primary Drinking Water Regulations. All information on public water system violations and estimates of impacted populations provided below are from the California Division of Drinking Water's (DDW) 2016 Annual Compliance Report.