Primacy Agency Drinking Water Data

Public water systems are regulated under the Safe Drinking Water Act and must follow national primary drinking water regulations established and enforced by the EPA to help protect public health. The EPA delegates primary enforcement responsibilities of public water systems to states, territories, and Indian Tribes, also known as primacy agencies, if they meet certain requirements. Otherwise, the EPA will administer primary enforcement responsibilities.

Drinking water data collected from public water systems are reported to primacy agencies by the public water systems on a monthly basis. The primacy agencies then report a subset of the drinking water data to the EPA where the EPA maintains these data in a federal database known as the Safe Drinking Water Information System, or SDWIS.

Data at the primacy agency level may be more up to date than at the federal level. Additionally, primacy agency data may contain more detailed information than federal level data, but information will vary from one primacy agency to the next. Data at the primacy agency level includes basic public water system information, violation information, and may include monitoring sample information. Whereas data at the federal level includes basic public water system information and violation information.

Some primacy agencies maintain a publicly accessible database that contains public water system information with varying degrees of detail. Find your state or territory to see if your primacy agency’s information is available. Each primacy agency listed has a link to the primacy agency's drinking water program's landing page and a link to their publicly accessible drinking water database, if available.