PFAS · Washington
PFAS in Washington drinking water: EPA’s final survey results
EPA’s national PFAS survey (UCMR 5) tested 245 of the community water systems that serve homes in Washington. 68 found at least one of 29 PFAS above the laboratory reporting level, and 20 had a PFOA or PFOS sampling-location yearly average at or above EPA’s 4.0 ppt limit. Samples were collected from January 2023 to May 2026.
Data as of EPA UCMR 5 final release, August 2026 (file dated Aug 28, 2026) · EPA SDWIS 2026Q2 (file dated Jul 9, 2026). How we build these pages
PFBS was the compound Washington community systems found most often: 52 of 245 tested systems measured it above the reporting level. Across the country, 35% of surveyed community systems found at least one PFAS; in Washington the share is 28%. The largest Washington system with a detection, Tacoma Water Division City of, serves 446,170 people and found 2 of the 29 compounds.
Which PFAS were found most often in Washington
Each row counts the Washington community water systems where that compound was measured above the reporting level at least once. A detection is a measurement, not a violation: most of these compounds have no federal limit.
| Compound | Systems where found | Systems tested | Share |
|---|---|---|---|
| PFBS | 52 | 245 | 21% |
| PFPeA | 35 | 245 | 14% |
| PFHxA | 31 | 245 | 13% |
| PFOS | 31 | 245 | 13% |
| PFHxS | 26 | 245 | 11% |
| PFOA | 18 | 245 | 7% |
| PFBA | 12 | 245 | 5% |
| PFHpA | 6 | 245 | 2% |
| PFPeS | 6 | 245 | 2% |
| 6:2 FTS | 1 | 245 | 0% |
| PFNA | 1 | 245 | 0% |
Washington systems with the most PFAS found
The 10 surveyed community water systems that found the most different PFAS, with PFOA and PFOS compared to EPA’s 4.0 ppt limits on the yearly average at the highest sampling location. Larger systems come first when counts tie.
| Water system | People served | PFAS found (of 29) | PFOA | PFOS |
|---|---|---|---|---|
| Richland City of WA5372250 | 106,499 | 8 | 0.0 ppt below the MCL | 0.0 ppt below the MCL |
| Artondale WA5303160 | 5,828 | 8 | 0.0 ppt below the MCL | 0.0 ppt below the MCL |
| Vancouver City of WA5391200 | 373,047 | 7 | 10.9 ppt at or above the MCL | 18.3 ppt at or above the MCL |
| Peacock Hill WA5366637 | 7,401 | 7 | — not detected above the reporting level | — not detected above the reporting level |
| Coupeville Town of WA5315550 | 4,142 | 7 | 4.9 ppt at or above the MCL | — not detected above the reporting level |
| Quistorff WA5370550 | 1,113 | 7 | — not detected above the reporting level | 11.5 ppt at or above the MCL |
| Lakehaven Water and Sewer District WA5341997 | 148,809 | 6 | — not detected above the reporting level | 2.1 ppt below the MCL |
| Kennewick City of WA5338100 | 118,164 | 6 | 2.2 ppt below the MCL | 10.0 ppt at or above the MCL |
| Sammamish Plateau Water & Sewer WA5340900 | 79,362 | 6 | — not detected above the reporting level | 9.7 ppt at or above the MCL |
| Southwood WA5382844 | 64,155 | 6 | 2.1 ppt below the MCL | 5.5 ppt at or above the MCL |
Counties with the most systems that found PFAS
- Pierce County 20 of 29 surveyed systems
- Spokane County 11 of 23 surveyed systems
- King County 9 of 41 surveyed systems
- Clark County 4 of 6 surveyed systems
- Kitsap County 4 of 18 surveyed systems
- Thurston County 3 of 7 surveyed systems
- Benton County 3 of 5 surveyed systems
- Snohomish County 2 of 20 surveyed systems