STATE / TERRITORY LEDGER
Wyoming drinking water system records
EPA’s September 2026 export lists 36 active community water systems in Wyoming, with 4 current-violation flags and 1 serious-violator flags among covered systems serving at least 2,500 people.
Source: EPA SDWIS system-search export · Active community systems · Snapshot 13 Sep 2026
Systems36active CWS · pop. 2,500+
Population served428,178reported total; may overlap
Current violation flag11.1%4 systems
Serious-violator flag2.8%1 systems
01 / LARGEST SYSTEMS
Wyoming community water systems
EPA’s covered Wyoming records include 36 active community systems reporting a combined population-served total of 428,178, which may overlap.
Population served is a system-reported service figure. It is not a count of unique state residents.
| Water system | Population served | Primary source | Current export status |
|---|---|---|---|
| Cheyenne Board Of Public UtilitiesWY5600011 | 64,165 | Surface water | No current violation flagged |
| Casper, City OfWY5601415 | 59,000 | Surface water purchased | No current violation flagged |
| Laramie, City OfWY5600029 | 32,395 | Surface water | No current violation flagged |
| Gillette, City OfWY5600019 | 32,222 | Ground water | No current violation flagged |
| Jackson, Town OfWY5600213 | 24,760 | Ground water | Current serious-violator flag |
| Rock Springs, City OfWY5601182 | 24,000 | Surface water purchased | No current violation flagged |
| Sheridan, City OfWY5600052 | 22,700 | Surface water | No current violation flagged |
| Evanston, City OfWY5600150 | 11,727 | Surface water | No current violation flagged |
| Green River, City OfWY5601181 | 10,500 | Surface water purchased | No current violation flagged |
| Riverton, City OfWY5600047 | 10,330 | Surface water | No current violation flagged |
| Cody, City OfWY5600207 | 10,224 | Surface water purchased | No current violation flagged |
| South Cheyenne Water & Sewer DistrictWY5600239 | 10,000 | Surface water purchased | No current violation flagged |
| Rawlins Water Supply, City OfWY5600045 | 9,006 | Surface water | Other current violation flag |
| Ynp-Old FaithfulWY5680085 | 7,675 | Surface water | No current violation flagged |
| Lander, City OfWY5600176 | 7,615 | Surface water | No current violation flagged |
| Northwest Rural Water DistrictWY5601254 | 7,330 | Surface water purchased | No current violation flagged |
| Torrington Municipal Water Dept, City OfWY5600164 | 6,847 | Ground water | No current violation flagged |
| Douglas, City OfWY5600137 | 6,400 | Surface water | No current violation flagged |
| Powell, City OfWY5600042 | 6,310 | Surface water purchased | No current violation flagged |
| Ynp - Lake VillageWY5680079 | 5,925 | Groundwater under influence of surface water | Current monitoring/reporting flag |
| Usaf F.E. Warren AfbWY5680122 | 5,500 | Surface water purchased | No current violation flagged |
| Worland Utilities CommissionWY5600197 | 4,787 | Ground water | No current violation flagged |
| Gtnp-Colter Bay VillageWY5680095 | 4,514 | Ground water | No current violation flagged |
| Buffalo, City OfWY5600005 | 4,419 | Surface water | No current violation flagged |
| Arapahoe Comm Water System085690004 | 4,100 | Ground water | No current violation flagged |
| Mills, City OfWY5600036 | 4,050 | Groundwater under influence of surface water | No current violation flagged |
| Bar Nunn, Town OfWY5600067 | 4,000 | Surface water purchased | No current violation flagged |
| Wheatland, Town OfWY5600187 | 3,659 | Ground water | Current health-based flag |
| Newcastle, City OfWY5600256 | 3,595 | Ground water | No current violation flagged |
| Kemmerer-Diamondville JpbWY5600028 | 3,348 | Surface water | No current violation flagged |
| Wright Water & Sewer DistrictWY5600136 | 3,207 | Ground water | No current violation flagged |
| White Mountain W&S DistrictWY5601391 | 3,000 | Surface water purchased | No current violation flagged |
| Evansville, Town OfWY5600018 | 2,873 | Surface water | No current violation flagged |
| Thermopolis, Town OfWY5600056 | 2,775 | Surface water | No current violation flagged |
| Fort Washakie085690003 | 2,620 | Surface water | No current violation flagged |
| Ynp-Mammoth Hot SpringsWY5680092 | 2,600 | Surface water | No current violation flagged |
02 / CITY REPORTS
Wyoming city water-system reports
Wyoming has 13 city reports meeting the publication threshold for covered systems or reported population served.
03 / COUNTY REPORTS
Wyoming county water-system reports
Wyoming has 10 county reports meeting the publication threshold for covered systems or reported population served.