An official website of the United States government.

This is not the current EPA website. To navigate to the current EPA website, please go to This website is historical material reflecting the EPA website as it existed on January 19, 2021. This website is no longer updated and links to external websites and some internal pages may not work. More information »

SDWIS Overview

SDWIS Banner

SDWIS iconInformation about ​safe drinking water is stored in SDWIS, the EPA's Safe Drinking Water Information System. SDWIS tracks information on drinking water contamination levels as required by the 1974 Safe Drinking Water Act and its 1986 and 1996 amendments. The Safe Drinking Water Act (SDWA) and accompanying regulations establish Maximum Contaminant Levels (MCLs), treatment techniques, and monitoring and reporting requirements to ensure that water provided to customers is safe for human consumption. The Safe Drinking Water Information System (SDWIS) contains information about public water systems and their violations of EPA's drinking water regulations. Searching SDWIS will allow you to locate your drinking water supplier and view its violations and enforcement history for the last ten years.