States → Wyoming
State profile · EPA SDWIS + UCMR5
Wyoming Drinking Water Quality
766 public water systems serve 639,288 people across Wyoming, with every Safe Drinking Water Act violation and UCMR5 PFAS result on record.
- 766
- Water systems
- 32,465
- Total violations
- 94.5%
- Systems w/ a violation
- 54.5%
- PFAS detection rate
The verdict
Across Wyoming, 724 of 766 water systems (94.5%) carry at least one EPA violation, and 18 of 33 UCMR5-tested systems show PFAS.
- 32,465
- Total EPA violations on record
- 12%
- Health-based (MCL / treatment)
- 94.5%
- Systems with ≥1 violation
- 54.5%
- UCMR5 PFAS detection rate
Water Systems
766
Total Violations
32,465
Violation Rate
94.5%
PFAS Detection
54.5%
18 of 33 tested
Violation Composition
How Wyoming's 32,465 violations break down by type, per EPA SDWIS classification.
Health-based (4,023) Monitoring/Reporting (28,442)
| Metric | Value | Share |
|---|---|---|
| Public water systems | 766 | - |
| Population served | 639,288 | - |
| Total violations | 32,465 | 100% |
| Health-based violations | 4,023 | 12.4% |
| Systems with violations | 724 | 94.5% |
| PFAS detection rate | 18 of 33 | 54.5% |
Health-based violations indicate the contaminant exceeded an EPA Maximum Contaminant Level (MCL) or treatment-technique requirement. Monitoring/reporting violations indicate procedural issues (missed tests, late reports) - not necessarily a contamination event.
Largest Water Systems
Cheyenne Board of Public Utilities
Cheyenne, WY · 64,165 served
Casper, City Of
Casper, WY · 59,000 served
Laramie, City Of
Laramie, WY · 32,395 served
Gillette, City Of
Gillette, WY · 32,222 served
Jackson, Town Of
Jackson, WY · 24,760 served
Rock Springs, City Of
Rock Springs, WY · 24,000 served
Sheridan, City Of
Sheridan, WY · 22,700 served
Evanston, City Of
Evanston, WY · 12,000 served
Green River, City Of
Green River, WY · 10,500 served
Riverton, City Of
Riverton, WY · 10,330 served
Cody, City Of
Cody, WY · 10,224 served
South Cheyenne Water & Sewer District
Cheyenne, WY · 10,000 served
Rawlins Water Supply, City Of
Rawlins, WY · 9,006 served
Ynp-Old Faithful
Yellowstone, WY · 7,675 served
Lander, City Of
Lander, WY · 7,615 served
Northwest Rural Water District
Cody, WY · 7,330 served
Torrington Municipal Water Dept, City Of
Torrington, WY · 6,847 served
Douglas, City Of
Douglas, WY · 6,400 served
Powell, City Of
Powell, WY · 6,310 served
Ynp - Lake Village
Yellowstone, WY · 5,925 served
Most Violations
#1 Marbleton, Town Of Marbleton
1,526 #2 Alcova Dam RV Park Casper
732 #3 Btnf-Blackrock Work Center Jackson
679 #4 Leisure Valley Inc/ Star Valley RV Park Grover
665 #5 Jeffrey City Water & Sewer District Jeffrey City
598 #6 Snake River Mobile Home Park Dallas
457 #7 Mountain Village Parks Jamestown
445 #8 Pine Bluffs, Town Of Fort Collins
391 #9 Hagens Estates Gillette
373 #10 Jade Mhc Riverton
367 #11 Lance Creek Water District Lance Creek
361 #12 Stroup Trailer Court Gillette
335 #13 Manville, Town Of Manville
314 #14 Broken Wrench LLC Casper
308 #15 Countryside Court Mills
301 Counties in Wyoming
Laramie
51 systems · 96,725 served
· 2,478 violations
Natrona
48 systems · 80,738 served
· 2,056 violations
Teton
116 systems · 78,802 served
· 5,306 violations
Sweetwater
47 systems · 53,285 served
· 1,717 violations
Campbell
68 systems · 51,714 served
· 2,720 violations
Albany
24 systems · 38,088 served
· 740 violations
Park
49 systems · 38,068 served
· 951 violations
Sheridan
21 systems · 27,820 served
· 524 violations
Fremont
60 systems · 26,396 served
· 2,787 violations
Uinta
13 systems · 20,786 served
· 338 violations
Lincoln
44 systems · 19,227 served
· 2,914 violations
Carbon
26 systems · 18,284 served
· 1,289 violations
Converse
19 systems · 14,323 served
· 520 violations
Big Horn
28 systems · 11,830 served
· 799 violations
Platte
28 systems · 10,003 served
· 995 violations
Goshen
17 systems · 9,851 served
· 510 violations
Crook
27 systems · 8,739 served
· 675 violations
Washakie
13 systems · 7,872 served
· 255 violations
Weston
12 systems · 6,536 served
· 726 violations
Sublette
28 systems · 6,181 served
· 2,695 violations
Johnson
13 systems · 5,523 served
· 351 violations
Hot Springs
8 systems · 4,429 served
· 261 violations
Niobrara
5 systems · 3,918 served
· 842 violations
Drinking Water Guides
Frequently Asked Questions
How many water systems are in Wyoming? ▼
Wyoming has 766 public water systems serving approximately 639,288 people. These include community water systems, non-transient non-community systems, and transient non-community systems regulated under the Safe Drinking Water Act.
How many drinking water violations are in Wyoming? ▼
Wyoming has 32,465 total drinking water violations on record, with 4,023 classified as health-based violations. 94.5% of water systems in the state have at least one violation.
Has PFAS been found in Wyoming drinking water? ▼
Of 33 water systems tested for PFAS in Wyoming, 18 had PFAS detected, a 54.5% detection rate. PFAS are persistent "forever chemicals" that do not break down in the environment.
What is the violation rate for Wyoming water systems? ▼
Wyoming's violation rate is 94.5%. This measures the percentage of public water systems that have at least one recorded violation in the EPA SDWIS database, including both health-based and monitoring/reporting violations.
Where does this Wyoming water data come from? ▼
All drinking water data comes from the EPA Safe Drinking Water Information System (SDWIS) and the UCMR5 PFAS monitoring program. SDWIS is the federal database that tracks compliance for all public water systems regulated under the Safe Drinking Water Act.
Data Sources & Methodology
Drinking water violation data from the EPA Safe Drinking Water Information System (SDWIS). PFAS testing data from the UCMR5 monitoring program. SDWIS tracks all public water systems regulated under the Safe Drinking Water Act.
Read our methodology - how this data is sourced, computed, and verified.
Related
Data sourced from EPA SDWIS and UCMR5 PFAS monitoring data. See our methodology for details. Retrieved and formatted by PlainWater Editorial
Every figure on PlainWater is rendered directly from EPA SDWIS drinking-water data, no number is typed in by an editor. This page draws directly on EPA SDWIS data, no figure is typed in by an editor. See our editorial standards & corrections policy, the methodology behind these numbers, or report a data error.