We found 11 public water systems in Grant county (ordered by population size).
| Name | Areas served | Population served | Contaminant count | Violation count |
|---|---|---|---|---|
| Grant-roberts Rural Water System | Milbank | 4,857 | 0 | 2 |
| Milbank | Milbank | 3,353 | 0 | 2 |
| Big Stone City | Big Stone City | 467 | 0 | 43 |
| Revillo | County of Grant | 119 | 0 | 0 |
| Strandburg | County of Grant | 74 | 0 | 0 |
| Twin Brooks | Twin Brooks | 69 | 0 | 0 |
| Riggin Trailer Park | County of Grant | 60 | 0 | 0 |
| Leroy's Campsite | County of Grant | 35 | 0 | 0 |
| Marvin | Marvin, South Shore | 30 | 0 | 0 |
| Hansen Mobile Home Park | County of Grant | 30 | 0 | 0 |
| Idlewild Resort | Idlewild Resort | 24 | 0 | 0 |