Tap Water Results

California tap water quality

2,920 community water systems serving 40 million people.

Data: U.S. EPA · How we read the data · How we check it

129
systems with PFAS above a federal limit
8.9 million
people served by them
691
systems EPA tested for PFAS
26
systems above the lead action level

PFAS: EPA's 2023–2025 testing. Lead: results from the last five years. 39 more systems have no recent lead results in EPA's database.

Water systems with PFAS above the federal limit

Based on EPA's UCMR 5 results (2023–2025) compared to the April 2024 limits, the way EPA compares them. Systems have until 2029 to comply. Largest first.

And 20 more in the full list of California utilities below.

California PFAS report: chart, rankings and data to download →

California's own PFAS limits

Notification level (not enforceable): PFOA 4 ppt, PFOS 4 ppt, PFHxS 3 ppt, PFBS 500 ppt, PFHxA 1000 ppt.

Response levels: PFOA 10, PFOS 40, PFHxS 10, PFBS 5,000, PFHxA 10,000 ppt. Above RL, ordered systems must remove source, treat, or notify. PFOA/PFOS/PFHxS/PFHxA levels issued 2025-10-29.

Source: California State Water Resources Control Board, Division of Drinking Water: PFAS, checked 2026-11-14. Utility pages compare each system's EPA results with these limits. State compliance is judged on the state's own sampling.

Largest water systems in California

California cities and towns

Most health-based violations since 2016

All California utilities on this site

Every California system serving 50,000+ people or with PFAS above a federal limit, A to Z. Download all 2,920 systems as CSV.

Questions

Does California tap water have PFAS?

EPA tested 691 community water systems in California for 29 PFAS between 2023 and 2025. 189 had at least one regulated PFAS detected, and 129 had an entry-point average above a 2024 federal limit. Those 129 systems serve about 8.9 million people (22% of people on community water in California). Systems have until 2029 to meet the limits.

How many California water systems have violations?

970 systems in California had at least one health-based violation since 2016 (6,563 violations in total). 1,268 violations are currently listed as unaddressed.

Which California water systems are over the lead action level?

26 systems had a lead 90th percentile above the 15 ppb action level in their most recent results from the last five years. Another 39 systems have no lead results in EPA's database from the last five years, including 1 whose last result was above the action level. Lead depends on each home's pipes, so a test of your own tap is the only way to know your level.

Source: U.S. EPA drinking water records and PFAS testing (UCMR 5). How we read the data.