We found 13 public water systems in Gregory county (ordered by population size).
| Name | Areas served | Population served | Contaminant count | Violation count |
|---|---|---|---|---|
| Tripp County Water User District | Hamill, Winner | 4,765 | 0 | 57 |
| Gregory | Gregory | 1,295 | 17 | 33 |
| Burke | Burke | 604 | 0 | 2 |
| Bonesteel | Bonesteel | 275 | 0 | 29 |
| East Gregory Rural Water System | County of Gregory | 188 | 0 | 0 |
| Fairfax | County of Gregory | 123 | 0 | 0 |
| Dallas | Dallas | 120 | 0 | 0 |
| Herrick | County of Gregory | 105 | 0 | 0 |
| Lucas Elementary School | Lucas | 55 | 0 | 0 |
| Gfp 6-a/burke Lake Well | County of Gregory | 50 | 0 | 0 |
| Coe Fr-56-260 Powerplant | County of Gregory | 40 | 0 | 0 |
| Coe Fr-64-110 Whetstone | County of Gregory | 25 | 0 | 0 |
| North Star Saloon | County of Gregory | 25 | 0 | 0 |