Water Quality in Wyoming
323 water systems • 108 cities • EPA SDWIS Data
323
Water Systems
13,783
Total Violations
742
Health-Based Violations
536,350
Population Served
Overview
Wyoming ranks 34th among all U.S. states for total drinking water violations, out of 51 states tracked. The state has 13,783 EPA Safe Drinking Water Act violations on record across 323 water systems serving 108 cities. Of those, 742 are health-based violations, meaning a regulated contaminant was measured above the EPA-established safe level. Wyoming's total violation count is 61% below the national average. Water systems in Wyoming serve approximately 536,350 people. The most frequently cited contaminants in Wyoming violations include Disinfection Byproducts, Total Haloacetic Acids (HAA5), Chlorine Dioxide, E. coli, Fecal Coliform.
Cities with Most Violations in Wyoming
| # | City | Violations | Health-Based | Water Systems | Population |
|---|---|---|---|---|---|
| 1 | Marbleton | 1,808 | 3 | 1 | 861 |
| 2 | Gillette | 1,070 | 41 | 47 | 45,958 |
| 3 | Grover | 904 | 15 | 9 | 3,179 |
| 4 | Jackson | 665 | 10 | 9 | 26,679 |
| 5 | Newcastle | 522 | 3 | 7 | 4,861 |
| 6 | Superior | 332 | 2 | 1 | 336 |
| 7 | Fort Collins | 323 | 15 | 2 | 1,261 |
| 8 | Cokeville | 323 | 17 | 1 | 535 |
| 9 | Burns | 313 | 0 | 1 | 1,024 |
| 10 | Wilson | 251 | 8 | 21 | 5,398 |
Largest Cities in Wyoming
| # | City | Population | Violations | Water Systems |
|---|---|---|---|---|
| 1 | Cheyenne | 77,707 | 135 | 14 |
| 2 | Casper | 66,524 | 192 | 14 |
| 3 | Gillette | 45,958 | 1,070 | 47 |
| 4 | Laramie | 33,950 | 71 | 6 |
| 5 | Rock Springs | 31,055 | 73 | 11 |
| 6 | Jackson | 26,679 | 665 | 9 |
| 7 | Sheridan | 23,785 | 35 | 3 |
| 8 | Cody | 17,896 | 25 | 4 |
| 9 | Yellowstone | 13,600 | 119 | 2 |
| 10 | Evanston | 12,362 | 8 | 2 |
All Cities in Wyoming
| City | Population | Violations | Health Violations | Contaminants |
|---|---|---|---|---|
| Cheyenne | 77,707 | 135 | 11 | Chlorine Dioxide, E. coli, Nitrate-Nitrite |
| Casper | 66,524 | 192 | 13 | Disinfection Byproducts, Fecal Coliform |
| Gillette | 45,958 | 1,070 | 41 | Chlorine Dioxide, Lead, Stage 2 DBP +1 more |
| Laramie | 33,950 | 71 | 1 | Bromate |
| Rock Springs | 31,055 | 73 | 1 | Stage 2 DBP |
| Jackson | 26,679 | 665 | 10 | Chlorine Dioxide, Disinfection Byproducts, E. coli |
| Sheridan | 23,785 | 35 | 5 | Disinfection Byproducts, Fecal Coliform, Total Haloacetic Acids (HAA5) |
| Cody | 17,896 | 25 | 1 | Stage 2 DBP |
| Yellowstone | 13,600 | 119 | 25 | Barium, Bromate, Disinfection Byproducts +1 more |
| Evanston | 12,362 | 8 | 3 | E. coli |
| Green River | 11,197 | 39 | 3 | E. coli |
| Riverton | 10,833 | 48 | 7 | Bromate, Chlorine Dioxide |
| Rawlins | 9,206 | 129 | 9 | Bromate, E. coli, Stage 2 DBP |
| Lander | 7,680 | 72 | 4 | E. coli |
| Torrington | 7,662 | 153 | 66 | Haloacetic Acids, Nitrate-Nitrite |
| Worland | 7,402 | 22 | 0 | |
| Douglas | 6,968 | 21 | 0 | |
| Powell | 6,781 | 5 | 0 | |
| Moose | 6,565 | 43 | 1 | Chlorine Dioxide |
| F.E. Warren Afb | 5,500 | 14 | 0 | |
| Wilson | 5,398 | 251 | 8 | Chlorine Dioxide, Disinfection Byproducts, Fecal Coliform |
| Newcastle | 4,861 | 522 | 3 | Chlorine Dioxide |
| Buffalo | 4,448 | 31 | 20 | Total Haloacetic Acids (HAA5) |
| Mills | 4,437 | 233 | 10 | Chlorine Dioxide, Stage 2 DBP, TTHM |
| Bar Nunn | 4,000 | 0 | 0 | |
| Thermopolis | 3,785 | 93 | 8 | Bromate, TTHM |
| Wheatland | 3,659 | 80 | 5 | Chlorine Dioxide, Haloacetic Acids |
| Greybull | 3,394 | 79 | 0 | |
| Kemmerer | 3,387 | 110 | 27 | TTHM, Total Haloacetic Acids (HAA5) |
| Grover | 3,179 | 904 | 15 | Chlorine Dioxide, E. coli, Fecal Coliform |
| Mountain View | 2,978 | 18 | 4 | Bromate, Total Haloacetic Acids (HAA5) |
| Yellowstone National Park | 2,600 | 5 | 0 | |
| Lovell | 2,510 | 8 | 0 | |
| Wright | 2,500 | 3 | 0 | |
| Pinedale | 2,480 | 11 | 1 | Disinfection Byproducts |
| Glenrock | 2,466 | 4 | 2 | Chlorine Dioxide |
| Afton | 2,281 | 213 | 7 | Chlorine Dioxide, Fecal Coliform |
| Lyman | 2,203 | 4 | 0 | |
| Star Valley Ranch | 2,030 | 18 | 5 | Chlorine Dioxide, E. coli, Gross Alpha |
| Little America | 2,004 | 29 | 26 | TTHM |
| Dubois | 1,938 | 172 | 1 | Disinfection Byproducts |
| Saratoga | 1,720 | 11 | 5 | Chlorine Dioxide |
| Alpine | 1,620 | 100 | 4 | Chlorine Dioxide |
| Farmington Hills | 1,590 | 2 | 0 | |
| Lusk | 1,576 | 62 | 3 | HAA5 |
| Basin | 1,360 | 11 | 1 | Chlorine Dioxide |
| Ranchester | 1,297 | 1 | 0 | |
| Pavillion | 1,281 | 93 | 17 | Chlorine Dioxide, Gross Alpha |
| Sundance | 1,279 | 3 | 1 | Chlorine Dioxide |
| Fort Collins | 1,261 | 323 | 15 | Chlorine Dioxide, Disinfection Byproducts, E. coli +1 more |
| Littleton | 1,260 | 27 | 2 | Bromate |
| Bear River | 1,200 | 9 | 4 | TTHM |
| Guernsey | 1,157 | 6 | 0 | |
| Upton | 1,100 | 1 | 1 | Chlorine Dioxide |
| Burns | 1,024 | 313 | 0 | |
| Moorcroft | 1,009 | 31 | 2 | Chlorine Dioxide |
| Teton Village | 906 | 4 | 0 | |
| Marbleton | 861 | 1,808 | 3 | Chlorine Dioxide |
| Hanna | 841 | 4 | 0 | |
| Cowley | 825 | 5 | 2 | Chlorine Dioxide |
| Dayton | 824 | 6 | 0 | |
| Bedford | 750 | 5 | 3 | Chlorine Dioxide |
| Smoot | 720 | 24 | 0 | |
| Byron | 593 | 4 | 0 | |
| Encampment | 580 | 34 | 1 | E. coli |
| Cokeville | 535 | 323 | 17 | Bromate, Chlorine Dioxide, E. coli +1 more |
| Shoshoni | 515 | 14 | 0 | |
| Wamsutter | 500 | 8 | 3 | Chlorine Dioxide |
| Lingle | 486 | 3 | 0 | |
| Sacramento | 475 | 11 | 0 | |
| Etna | 465 | 225 | 0 | |
| Hudson | 460 | 8 | 2 | Disinfection Byproducts, Fecal Coliform |
| Rolling Hills | 450 | 1 | 0 | |
| La Grange | 448 | 0 | 0 | |
| Big Piney | 445 | 46 | 1 | Chlorine Dioxide |
| Sinclair | 433 | 6 | 0 | |
| Hulett | 420 | 0 | 0 | |
| Midwest | 410 | 1 | 0 | |
| Baggs | 400 | 84 | 48 | Bromate, TTHM, Total Haloacetic Acids (HAA5) |
| Thayne | 400 | 43 | 2 | Chlorine Dioxide |
| Ten Sleep | 400 | 15 | 0 | |
| Cedaredge | 375 | 10 | 1 | Chlorine Dioxide |
| Meeteetse | 362 | 10 | 1 | Chlorine Dioxide |
| Burlington | 348 | 81 | 7 | Disinfection Byproducts |
| La Barge | 347 | 13 | 5 | Bromate, Fecal Coliform |
| Superior | 336 | 332 | 2 | Disinfection Byproducts |
| Glendo | 289 | 27 | 0 | |
| Kaycee | 263 | 5 | 0 | |
| East Thermopolis | 254 | 1 | 0 | |
| Osage | 240 | 17 | 1 | Chlorine Dioxide |
| Fort Laramie | 230 | 19 | 0 | |
| Rock River | 211 | 3 | 0 | |
| Chugwater | 200 | 73 | 2 | Chlorine Dioxide |
| Edgerton | 195 | 4 | 0 | |
| Elk Mountain | 191 | 222 | 2 | Chlorine Dioxide |
| Medicine Bow | 189 | 12 | 4 | Chlorine Dioxide |
| Albin | 181 | 121 | 3 | Chlorine Dioxide, Stage 2 DBP |
| Deaver | 176 | 1 | 0 | |
| Frannie | 160 | 5 | 0 | |
| Centennial | 150 | 16 | 2 | Chlorine Dioxide |
| American Fork | 148 | 0 | 0 | |
| Clearmont | 142 | 6 | 0 | |
| Granger | 139 | 34 | 6 | Bromate, E. coli, TTHM |
| Yoder | 131 | 3 | 1 | Gross Alpha |
| Evansville | 125 | 27 | 0 | |
| Shell | 120 | 2 | 0 | |
| Dixon | 114 | 106 | 93 | Bromate, TTHM, Total Haloacetic Acids (HAA5) |
| Dallas | 100 | 68 | 7 | Chlorine Dioxide, Disinfection Byproducts, Fecal Coliform +1 more |
Water Quality in Other States
Alabama 13,972 violations Alaska 73,527 violations Arizona 60,414 violations Arkansas 17,031 violations California 39,276 violations Colorado 42,596 violations Connecticut 28,800 violations Delaware 1,242 violations District of Columbia 115 violations Florida 36,335 violations Georgia 32,159 violations Hawaii 182 violations Idaho 26,078 violations Illinois 30,544 violations Indiana 18,261 violations Iowa 9,389 violations Kansas 19,480 violations Kentucky 9,427 violations Louisiana 32,039 violations Maine 6,830 violations Maryland 5,321 violations Massachusetts 10,561 violations Michigan 15,820 violations Minnesota 3,784 violations Mississippi 25,296 violations Missouri 25,377 violations Montana 20,202 violations Nebraska 5,134 violations Nevada 8,167 violations New Hampshire 6,968 violations New Jersey 19,332 violations New Mexico 37,115 violations New York 93,834 violations North Carolina 54,399 violations North Dakota 8,431 violations Ohio 61,604 violations Oklahoma 128,472 violations Oregon 0 violations Pennsylvania 199,265 violations Rhode Island 0 violations South Carolina 13,045 violations South Dakota 19,565 violations Tennessee 20,607 violations Texas 263,180 violations Utah 71,655 violations Vermont 12,362 violations Virginia 15,298 violations Washington 54,459 violations West Virginia 81,622 violations Wisconsin 18,533 violations
Data Sources
Drinking water data from the EPA Safe Drinking Water Information System (SDWIS). Only active community water systems (CWS) serving 100+ people are included.