Wyoming tap water quality

327 active community water systems.

Largest water systems

GradeSystemPeopleHealth violations (5y)
ACheyenne Board of Public Utilities64,1650
ACity of Casper59,0000
ACity of Laramie32,3950
ACity of Gillette32,2220
BTown of Jackson24,7600
ACity of Rock Springs24,0000
ACity of Sheridan22,7000
ACity of Evanston11,7270
ACity of Green River10,5000
CCity of Riverton10,3301
ACity of Cody10,2240
ASouth Cheyenne Water & Sewer District10,0000
CCity of Rawlins Water Supply9,0062
DYnp-Old Faithful7,7459
BCity of Lander7,6151
ANorthwest Rural Water District7,3300
ACity of Torrington Municipal Water Dept6,8470
ACity of Douglas6,4000
ACity of Powell6,3100
BYnp - Lake Village5,9250
AUSAF F.E. Warren AFB5,5000
AWorland Utilities Commission4,7870
AGtnp-Colter Bay Village4,5140
DCity of Buffalo4,4196
AArapahoe Comm Water System4,1000
CCity of Mills4,0503
ATown of Bar Nunn4,0000
DTown of Wheatland3,6593
BCity of Newcastle3,5950
DKemmerer-Diamondville Jpb3,34811
AWright Water & Sewer District3,2070
AWhite Mountain W&s District3,0000
BTown of Star Valley Ranch2,8941
ATown of Evansville2,8730
ATown of Thermopolis2,7750
AFort Washakie2,6200
AYnp-Mammoth Hot Springs2,6000
BTown of Glenrock2,4661
ASleepy Hollow Subdivision2,4000
ATown of Lovell2,2500
ATown of Lyman2,2030
BTown of Greybull2,0800
BPinedale Municipal WS2,0050
ALittle America Hotels & Resorts, Inc- Wy2,0040
AAfton, Board of Pub Utilities2,0000
CEthete Water System1,9502
DLeisure Valley Inc/ Star Valley RV Park1,8973
AGtnp-Jackson Lake Lodge1,8300
BTown of Dubois1,8221
BBridger Valley Joint Powers Board1,7281

Most issues (systems serving 10,000+)

C

City of Riverton

Serves 10,330 people · Surface water · Full report →
1 health-based violation in the last 5 years; 3 monitoring/reporting violations; Other PFAS above 2024 limits (rule proposed for repeal): PFHxS, Hazard Index; Lead 90th percentile below the action level (2023).
B

Town of Jackson

Serves 24,760 people · Groundwater · Full report →
No health-based violations in the last 5 years; 187 monitoring/reporting violations; PFAS tested (UCMR 5), none above federal limits; Lead 90th percentile below the action level (2026).
A

City of Cody

Serves 10,224 people · Surface water · Full report →
No health-based violations in the last 5 years; 3 monitoring/reporting violations; PFAS tested (UCMR 5), none above federal limits; Lead 90th percentile below the action level (2025).
A

City of Gillette

Serves 32,222 people · Groundwater · Full report →
No health-based violations in the last 5 years; 2 monitoring/reporting violations; PFAS tested (UCMR 5), none above federal limits; Lead 90th percentile below the action level (2025).
A

City of Green River

Serves 10,500 people · Surface water · Full report →
No health-based violations in the last 5 years; 2 monitoring/reporting violations; PFAS tested (UCMR 5), none above federal limits; Lead 90th percentile below the action level (2025).
A

City of Laramie

Serves 32,395 people · Surface water · Full report →
No health-based violations in the last 5 years; 1 monitoring/reporting violation; PFAS tested (UCMR 5), none above federal limits; Lead 90th percentile below the action level (2024).
A

South Cheyenne Water & Sewer District

Serves 10,000 people · Surface water · Full report →
No health-based violations in the last 5 years; 1 monitoring/reporting violation; PFAS tested (UCMR 5), none above federal limits; Lead 90th percentile below the action level (2023).
A

Cheyenne Board of Public Utilities

Serves 64,165 people · Surface water · Full report →
No health-based violations in the last 5 years; PFAS tested (UCMR 5), none above federal limits; Lead 90th percentile above the new 10 ppb action level (LCRI, effective Nov 1, 2027); Lead 90th percentile below the action level (2025).
A

City of Casper

Serves 59,000 people · Surface water · Full report →
No health-based violations in the last 5 years; PFAS tested (UCMR 5), none above federal limits; Lead 90th percentile below the action level (2023).
A

City of Rock Springs

Serves 24,000 people · Surface water · Full report →
No health-based violations in the last 5 years; PFAS tested (UCMR 5), none above federal limits; Lead 90th percentile below the action level (2025).
A

City of Sheridan

Serves 22,700 people · Surface water · Full report →
No health-based violations in the last 5 years; PFAS tested (UCMR 5), none above federal limits; Lead 90th percentile below the action level (2023).
A

City of Evanston

Serves 11,727 people · Surface water · Full report →
No health-based violations in the last 5 years; PFAS tested (UCMR 5), none above federal limits; Lead 90th percentile below the action level (2025).

Cities

AftonAlbinAlpineAltaArapahoeBaggsBairoilBasinBedfordBeulahBig PineyBoulderBuffaloBurlingtonBurnsByronCarpenterCasperCentennialCheyenneChugwaterClearmontCodyCokevilleCoraCowleyDanielDaytonDeaverDiamondvilleDixonDouglasDuboisEdgertonElk MountainEncampmentEtnaEvanstonEvansvilleFairviewFarsonFe Warren AfbFort LaramieFort WashakieFour CornersFrannieFreedomGilletteGlendoGlenrockGrangerGreen RiverGreybullGroverGuernseyHannaHartvilleHawk SpringsHudsonHulettHyattvilleJacksonJay EmKayceeKemmererKinnearKirbyLA BargeLA GrangeLance CreekLanderLaramieLingleLittle AmericaLost SpringsLovellLuskLymanMandersonManvilleMarbletonMedicine BowMeeteetseMidwestMillsMoorcroftMooseMoranMoran JctMountain ViewNewcastleOpalOsageOttoPavillionPine BluffsPine HavenPinedalePoint of RocksPowellRalstonRanchesterRawlinsRelianceRivertonRock RiverRock SpringsRolling HillsRozetSaratogaShellSheridanShoshoniSinclairSmootStar Valley RanchSundanceSuperiorTen SleepTeton VillageThayneThermopolisTorringtonUptonWalcottWamsutterWapitiWheatlandWilsonWolfWorlandWrightYellowstone National ParkYellowstone NpYellowstone NtYoder