EPA data as of Oct 2026 · page updated 2026-10-29

Wyoming: drinking water & radon

Wyoming has 316 active community water systems. Since 2016, 109 reported health-based violations; 0 had a latest lead result above 15 ppb; 2 measured PFOA or PFOS at or above 4 ppt.

Water systems316

With violations109

Radon zone 1 ZIPs184

ZIPs likely on wells126

Radon zones in Wyoming

tap a county

Zone 1 · highestZone 2 · moderateZone 3 · low

Most health-based violations

Lance Creek Water District 55 people	33
Town of Dixon 114 people	28
Little America Hotels & Resorts, INC- Wy 2,004 people	20
Cottonwood Acres 95 people	16
Town of Baggs 400 people	14
YNP-OLD Faithful 7,745 people	11
Kemmerer-Diamondville JPB 3,348 people	11
Stone Creek HOA 100 people	9
Town of Cokeville 535 people	8
Potlatch Trailer Court 70 people	8

Highest latest lead (90th percentile)

Town of Opal 65 people	15 ppb
Cheyenne Board of Public Utilities 64,165 people	15 ppb
Ten Mile Water and Sewer District 305 people	14 ppb
Town of Manderson 110 people	13 ppb
First Fike Subdivision 150 people	11 ppb
Veterans Administration Medical Center 802 people	10 ppb
Town of Baggs 400 people	9 ppb
Town of Star Valley Ranch 2,894 people	8 ppb
Town of Chugwater 200 people	8 ppb
Saddle Butte Water System 75 people	7 ppb

Highest PFOA / PFOS

Fort Washakie 2,620 people	9.3 ppt
City of Riverton 10,330 people	7 ppt

Largest systems

Cheyenne Board of Public Utilities 64,165 people	64,165
City of Casper 59,000 people	59,000
City of Laramie 32,395 people	32,395
City of Gillette 32,222 people	32,222
Town of Jackson 24,760 people	24,760
City of Rock Springs 24,000 people	24,000
City of Sheridan 22,700 people	22,700
City of Evanston 11,727 people	11,727
City of Green River 10,500 people	10,500
City of Riverton 10,330 people	10,330

All ZIP codes in Wyoming

192 ZIP codes.

82001Cheyenne 82002Cheyenne 82003Cheyenne 82005Fe Warren Afb 82006Cheyenne 82007Cheyenne 82009Cheyenne 82010Cheyenne 82050Albin 82051Bosler 82052Buford 82053Burns 82054Carpenter 82055Centennial 82058Garrett 82059Granite Canon 82060Hillsdale 82061Horse Creek 82063Jelm 82070Laramie 82072Laramie 82073Laramie 82081Meriden 82082Pine Bluffs 82083Rock River 82084Tie Siding 82190Yellowstone National Park 82201Wheatland 82210Chugwater 82212Fort Laramie 82213Glendo 82214Guernsey 82215Hartville 82217Hawk Springs 82218Huntley 82219Jay Em 82221Lagrange 82222Lance Creek 82223Lingle 82224Lost Springs 82225Lusk 82227Manville 82229Shawnee 82240Torrington 82242Van Tassell 82243Veteran 82244Yoder 82301Rawlins 82310Jeffrey City 82321Baggs 82322Bairoil 82323Dixon 82324Elk Mountain 82325Encampment 82327Hanna 82329Medicine Bow 82331Saratoga 82332Savery 82334Sinclair 82335Walcott 82336Wamsutter 82401Worland 82410Basin 82411Burlington 82412Byron 82414Cody 82420Cowley 82421Deaver 82422Emblem 82423Frannie 82426Greybull 82428Hyattville 82430Kirby 82431Lovell 82432Manderson 82433Meeteetse 82434Otto 82435Powell 82440Ralston 82441Shell 82442Ten Sleep 82443Thermopolis 82450Wapiti 82501Riverton 82510Arapahoe 82512Crowheart 82513Dubois 82514Fort Washakie 82515Hudson 82516Kinnear 82520Lander 82523Pavillion 82524Saint Stephens 82601Casper 82602Casper 82604Casper 82605Casper 82609Casper 82615Shirley Basin 82620Alcova 82630Arminto 82633Douglas 82635Edgerton 82636Evansville 82637Glenrock 82638Hiland 82639Kaycee 82640Linch 82642Lysite 82643Midwest 82644Mills 82646Natrona 82648Powder River 82649Shoshoni 82701Newcastle 82710Aladdin 82711Alva 82712Beulah 82714Devils Tower 82716Gillette 82717Gillette 82718Gillette 82720Hulett 82721Moorcroft 82723Osage 82725Recluse 82727Rozet 82729Sundance 82730Upton 82731Weston 82732Wright 82801Sheridan 82831Arvada 82832Banner 82833Big Horn 82834Buffalo 82835Clearmont 82836Dayton 82837Leiter 82838Parkman 82839Ranchester 82840Saddlestring 82842Story 82844Wolf 82845Wyarno 82901Rock Springs 82902Rock Springs 82922Bondurant 82923Boulder 82925Cora 82929Little America 82930Evanston 82931Evanston 82932Farson 82933Fort Bridger 82934Granger 82935Green River 82936Lonetree 82937Lyman 82938Mc Kinnon 82939Mountain View 82941Pinedale 82942Point Of Rocks 82943Reliance 82944Robertson 82945Superior 83001Jackson 83002Jackson 83011Kelly 83012Moose 83013Moran 83014Wilson 83025Teton Village 83101Kemmerer 83110Afton 83111Auburn 83112Bedford 83113Big Piney 83114Cokeville 83115Daniel 83116Diamondville 83118Etna 83119Fairview 83120Freedom 83121Frontier 83122Grover 83123La Barge 83124Opal 83126Smoot 83127Thayne 83128Alpine 83414Alta

What this is — and isn’t. These are records your water utility and state reported to the EPA, and the EPA’s radon map for your county. They describe the system and the area, not the water from your own tap or the air in your home. For that, read your utility’s annual Consumer Confidence Report and test: lead and radon tests are inexpensive.

Questions

How many water systems in Wyoming have violations?

109 of 316 active community water systems in Wyoming reported at least one health-based violation since 2016 (EPA SDWIS).

What is the radon risk in Wyoming?

184 ZIP codes are in EPA radon zone 1 (highest potential), 8 in zone 2 and 0 in zone 3. EPA recommends testing every home.