Tap Water Results

Washington tap water quality

2,374 community water systems serving 9.6 million people.

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

20
systems with PFAS above a federal limit
1.2 million
people served by them
245
systems EPA tested for PFAS
17
systems above the lead action level

PFAS: EPA's 2023–2025 testing. Lead: results from the last five years. 98 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.

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

Washington's own PFAS limits

State action level (SAL) (not enforceable): PFOA 4 ppt, PFOS 4 ppt, PFHxS 10 ppt, PFNA 10 ppt, HFPO-DA 10 ppt.

WAC 246-290-315 Table 9 SALs (plus Hazard Index 1) trigger mandatory follow-up under WAC 246-290-320. SALs are not state MCLs.

Source: WAC 246-290-315 State action levels (SALs) and state maximum contaminant levels (MCLs), 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 Washington

Washington cities and towns

Most health-based violations since 2016

All Washington utilities on this site

Every Washington system serving 50,000+ people or with PFAS above a federal limit, A to Z. Download all 2,374 systems as CSV.

Questions

Does Washington tap water have PFAS?

EPA tested 245 community water systems in Washington for 29 PFAS between 2023 and 2025. 41 had at least one regulated PFAS detected, and 20 had an entry-point average above a 2024 federal limit. Those 20 systems serve about 1.2 million people (12% of people on community water in Washington). Systems have until 2029 to meet the limits.

How many Washington water systems have violations?

259 systems in Washington had at least one health-based violation since 2016 (1,160 violations in total). 157 violations are currently listed as unaddressed.

Which Washington water systems are over the lead action level?

17 systems had a lead 90th percentile above the 15 ppb action level in their most recent results from the last five years. Another 98 systems have no lead results in EPA's database from the last five years, including 7 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.