Wyoming tap water quality

327 community water systems serving 545,237 people.

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

systems with PFAS above a federal limit

10,330

people served by them

systems EPA tested for PFAS

systems above the lead action level

PFAS: EPA's 2023–2025 testing. Lead: results from the last five years. 1 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.

City of Riverton
10,330 people · Surface water · Wyoming
PFHxS above limitAlso: PFAS Hazard Index above limit · PFOS detected · 2 health-based violations since 2016

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

Largest water systems in Wyoming

Cheyenne Board of Public Utilities
64,165 people · Surface water · Wyoming
Lead near 2027 level
City of Casper
59,000 people · Purchased surface water · Wyoming
Lithium above screening level
City of Laramie
32,395 people · Surface water · Wyoming
No PFAS above limits
City of Gillette
32,222 people · Groundwater · Wyoming
No PFAS above limits
Town of Jackson
24,760 people · Groundwater · Wyoming
PFHxS detectedAlso: Lithium above screening level
City of Rock Springs
24,000 people · Purchased surface water · Wyoming
Lithium above screening level
City of Sheridan
22,700 people · Surface water · Wyoming
No PFAS above limits
City of Evanston
11,727 people · Surface water · Wyoming
No PFAS above limits
City of Green River
10,500 people · Purchased surface water · Wyoming
No PFAS above limits
City of Riverton
10,330 people · Surface water · Wyoming
PFHxS above limitAlso: PFAS Hazard Index above limit · PFOS detected · 2 health-based violations since 2016
City of Cody
10,224 people · Purchased surface water · Wyoming
No PFAS above limits
South Cheyenne Water & Sewer District
10,000 people · Purchased surface water · Wyoming
No PFAS above limits
City of Rawlins Water Supply
9,006 people · Surface water · Wyoming
Lithium above screening levelAlso: 5 health-based violations since 2016
Ynp-Old Faithful Water System
7,745 people · Surface water · Wyoming
Arsenic violationsAlso: Lithium above screening level
City of Lander
7,615 people · Surface water · Wyoming
No PFAS above limitsAlso: 1 health-based violation since 2016

Wyoming cities and towns

Most health-based violations since 2016

Lance Creek Water District
55 people · Groundwater · Wyoming
Radium (combined 226/228) violationsAlso: Gross alpha violations · Coliform bacteria violation · Lead near 2027 level
Town of Dixon
114 people · Groundwater under influence of surface water · Wyoming
Haloacetic acids (HAA5) violationsAlso: Total trihalomethanes (TTHM) violations
Little America Hotels & Resorts, Inc – Wy
2,004 people · Surface water · Wyoming
Total trihalomethanes (TTHM) violations
Cottonwood Acres Water System
95 people · Groundwater · Wyoming
Nitrate-nitrite violationsAlso: Uranium violations
Town of Baggs
400 people · Groundwater under influence of surface water · Wyoming
Haloacetic acids (HAA5) violationsAlso: Total trihalomethanes (TTHM) violations
Ynp-Old Faithful Water System
7,745 people · Surface water · Wyoming
Arsenic violationsAlso: Lithium above screening level
Kemmerer-Diamondville Jpb Water System
3,348 people · Surface water · Wyoming
Total trihalomethanes (TTHM) violationsAlso: Haloacetic acids (HAA5) violations
Stone Creek HOA
100 people · Groundwater · Wyoming
Nitrate-nitrite violations
Town of Cokeville
535 people · Groundwater · Wyoming
Coliform bacteria violations
Potlatch Trailer Court Water System
70 people · Groundwater · Wyoming
Nitrate-nitrite violations
Broken Wrench LLC
30 people · Groundwater · Wyoming
Not in EPA's PFAS sampleAlso: 7 health-based violations since 2016
Town of Manville
97 people · Groundwater · Wyoming
Uranium violations
Town of Pine Bluffs
1,186 people · Groundwater · Wyoming
Nitrate-nitrite violation
Rozet Ranchettes I&s District
85 people · Groundwater · Wyoming
Fluoride violations
City of Buffalo
4,419 people · Surface water · Wyoming
Haloacetic acids (HAA5) violations

All Wyoming utilities on this site

Every Wyoming system serving 50,000+ people or with PFAS above a federal limit, A to Z. Download all 327 systems as CSV.

Questions

Does Wyoming tap water have PFAS?

EPA tested 32 community water systems in Wyoming for 29 PFAS between 2023 and 2025. 3 had at least one regulated PFAS detected, and 1 had an entry-point average above a 2024 federal limit. Those 1 systems serve about 10,330 people (2% of people on community water in Wyoming). Systems have until 2029 to meet the limits.

How many Wyoming water systems have violations?

114 systems in Wyoming had at least one health-based violation since 2016 (376 violations in total). 89 violations are currently listed as unaddressed.

Which Wyoming water systems are over the lead action level?

0 systems had a lead 90th percentile above the 15 ppb action level in their most recent results from the last five years. Another 1 system has no lead results in EPA's database from the last five years. 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.