National lookup

What does EPA know about your water?

Search 17,672 US water systems against EPA's own records: PFAS monitoring results, lead levels, and every Safe Drinking Water Act violation on file. Covering 322,630,202 people across 58 states and territories.

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What these figures mean

PFAS comes from EPA's UCMR 5 programme, which tested every system serving more than 3,300 people for 29 PFAS compounds between 2023 and 2025. A non-detect is a real result. A system with no record was not tested, which is not the same as being clean, and we label those differently for that reason.

Lead is a 90th-percentile figure from Lead and Copper Rule tap sampling: nine in ten sampled homes measured at or below it. It is not a maximum, and lead enters through service lines and household plumbing rather than the treatment plant, so your address matters more than your city.

Violations counts health-based Safe Drinking Water Act violations only, where a contaminant exceeded a legal limit or required treatment was not delivered. Monitoring and paperwork failures are excluded, because they describe process rather than water. Large systems accumulate more violations mechanically, so a recent pattern matters more than a raw total. Full national analysis.

Common questions

How do I find out what's in my tap water?
Search your city here. Search your city or utility name. We hold EPA records for 17,672 community water systems serving 322 million people: PFAS results from UCMR 5 monitoring, lead 90th-percentile figures from Lead and Copper Rule sampling, and Safe Drinking Water Act violation history. Everything shown comes from EPA's published compliance data.
What water system serves my address?
Search your city and this tool lists every community water system EPA records as serving it, largest first. Many cities are served by more than one system, and results can differ between them, so check which one covers your address if several appear.
Is my tap water safe to drink?
Legal compliance and health optimality are different questions. This tool shows whether a system has recorded health-based violations and whether PFAS was detected during EPA monitoring. A system can meet every legal standard and still carry readings above health-based guidance, which is what our city scores measure separately.
Why isn't my city listed?
We index systems serving 1,000 people or more. Smaller systems, private wells and some rural districts are excluded. Well water is not regulated under the Safe Drinking Water Act at all, so no federal record exists for it.

The 50 largest systems, scored in full

Where we have read the utility’s own annual report, cities get a complete contaminant breakdown and a score against health guidance.

Scored city pages PFAS by state