PFAS · Wyoming
PFAS in Wyoming drinking water: EPA’s final survey results
EPA’s national PFAS survey (UCMR 5) tested 32 of the community water systems that serve homes in Wyoming. 4 found at least one of 29 PFAS above the laboratory reporting level, and 0 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 December 2025.
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
PFBA was the compound Wyoming community systems found most often: 2 of 32 tested systems measured it above the reporting level. Across the country, 35% of surveyed community systems found at least one PFAS; in Wyoming the share is 13%. The largest Wyoming system with a detection, Jackson, Town of, serves 24,760 people and found 1 of the 29 compounds.
Which PFAS were found most often in Wyoming
Each row counts the Wyoming 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 |
|---|---|---|---|
| PFBA | 2 | 32 | 6% |
| PFHxS | 2 | 32 | 6% |
| PFBS | 1 | 32 | 3% |
| PFHpA | 1 | 32 | 3% |
| PFHxA | 1 | 32 | 3% |
| PFOA | 1 | 32 | 3% |
| PFOS | 1 | 32 | 3% |
| PFPeA | 1 | 32 | 3% |
| PFPeS | 1 | 32 | 3% |
Wyoming systems with the most PFAS found
The 4 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 |
|---|---|---|---|---|
| Riverton, City of WY5600047 | 10,330 | 8 | — not detected above the reporting level | 3.5 ppt below the MCL |
| Jackson, Town of WY5600213 | 24,760 | 1 | — not detected above the reporting level | — not detected above the reporting level |
| Douglas, City of WY5600137 | 6,400 | 1 | — not detected above the reporting level | — not detected above the reporting level |
| Fort Washakie 085690003 | 2,620 | 1 | 2.3 ppt below the MCL | — not detected above the reporting level |
Counties with the most systems that found PFAS
- Teton County 1 of 3 surveyed systems
- Fremont County 1 of 3 surveyed systems
- Converse County 1 of 1 surveyed systems