PFAS Testing Results
Wyoming
PFAS testing results for 33 water systems serving 410,041 residents.
1 system exceeds federal PFAS limits, affecting 10,330 residents.
Systems tested
33
9.1% had PFAS detections
Limits exceeded
1
3.0% of systems
Population affected
10K
served by systems over federal limits
Most common compound
11Cl-PF3OUdS
detected in 3 systems
Grade distribution
Every water system gets a letter grade based on how its worst detected PFAS compound compares to the federal Maximum Contaminant Level. Lower grades mean higher contamination.
Communities exceeding federal limits
The water systems in Wyoming where at least one PFAS compound exceeds the EPA Maximum Contaminant Level, sorted worst first.
| System name | City | Grade | Worst compound | Times over limit | Population |
|---|---|---|---|---|---|
| RIVERTON, CITY OF | RIVERTON | D | PFHxS | 3.7x | 10K |
Resources for taking action are available in our community toolkit.
What Wyoming is doing about PFAS
As of April 2026, Wyoming has not adopted state-level PFAS drinking water standards beyond the federal EPA limits finalized in April 2024. The Wyoming Department of Environmental Quality has tracked contamination near Francis E. Warren Air Force Base outside Cheyenne.
Public water systems in Wyoming are subject to the federal compliance timeline requiring initial monitoring by 2027 and treatment installation by 2029.
Based on Wyoming Department of Environmental Quality publications.
All 33 tested water systems in Wyoming
Sorted from lowest grade to highest. Click any system name for the full report. Filter by city or name with the search box below.
Showing 33 of 33 systems
| Grade | System name | City | Worst compound | vs. EPA limit | Population |
|---|---|---|---|---|---|
D | RIVERTON, CITY OF | RIVERTON | PFHxS | 3.7× the federal limit | 10K |
B | JACKSON, TOWN OF | JACKSON | PFHxS | Below federal limit | 25K |
B | DOUGLAS, CITY OF | DOUGLAS | PFBA | Below detection | 6.4K |
A | BUFFALO, CITY OF | BUFFALO | - | Below detection | 4.4K |
A | CHEYENNE BOARD OF PUBLIC UTILITIES | CHEYENNE | - | Below detection | 64K |
A | GILLETTE, CITY OF | GILLETTE | - | Below detection | 32K |
A | KEMMERER-DIAMONDVILLE JPB | KEMMERER | - | Below detection | 3.3K |
A | LARAMIE, CITY OF | LARAMIE | - | Below detection | 32K |
A | LOVELL, TOWN OF | LOVELL | - | Below detection | 2.4K |
A | MILLS, TOWN OF | MILLS | - | Below detection | 4.0K |
A | POWELL, CITY OF | POWELL | - | Below detection | 6.3K |
A | RAWLINS WATER SUPPLY, CITY OF | RAWLINS | - | Below detection | 9.0K |
A | SHERIDAN WY, CITY OF | SHERIDAN | - | Below detection | 23K |
A | WARDWELL WATER & SEWER DISTRICT | BAR NUNN | - | Below detection | 4.0K |
A | EVANSTON, CITY OF | EVANSTON | - | Below detection | 12K |
A | TORRINGTON MUNICIPAL WS | TORRINGTON | - | Below detection | 6.8K |
A | LANDER, CITY OF | LANDER | - | Below detection | 7.6K |
A | WHEATLAND, TOWN OF | WHEATLAND | - | Below detection | 3.7K |
A | FIRST FIKE SUBDIVISION | PAVILLION | - | Below detection | 150 |
A | WORLAND UTILITIES COMMISSION | WORLAND | - | Below detection | 5.5K |
A | CODY, CITY OF | CODY | - | Below detection | 10K |
A | SOUTH CHEYENNE WATER & SEWER DISTRICT | CHEYENNE | - | Below detection | 10K |
A | NEWCASTLE, CITY OF | NEWCASTLE | - | Below detection | 3.6K |
A | BLACK THUNDER COAL MINE | WRIGHT | - | Below detection | 600 |
A | GREEN RIVER, CITY OF | GREEN RIVER | - | Below detection | 11K |
A | ROCK SPRINGS, CITY OF | ROCK SPRINGS | - | Below detection | 24K |
A | NORTHWEST RURAL WATER DISTRICT, WY | CODY | - | Below detection | 7.3K |
A | CASPER, CITY OF | CASPER | - | Below detection | 59K |
A | HIGH MEADOW RANCH | PINEDALE | - | Below detection | 580 |
A | YNP-CANYON VILLAGE | YELLOWSTONE | - | Below detection | 4.3K |
A | YNP-OLD FAITHFUL | YELLOWSTONE | - | Below detection | 7.7K |
A | GTNP-COLTER BAY VILLAGE | MOOSE | - | Below detection | 4.5K |
A | USAF F.E. WARREN AFB | F.E. WARREN AFB | - | Below detection | 5.5K |
Check your water system
Enter your zip code to see the PFAS results for the water system that serves your home.
Where this data comes from
- EPA Unregulated Contaminant Monitoring Rule, 5th cycle (UCMR 5)
- Testing period: 2023 to 2026
- Federal limits: EPA Maximum Contaminant Levels finalized April 2024
- Read the full methodology