We found 16 public water systems in Hamlin county (ordered by population size).
| Name | Areas served | Population served | Contaminant count | Violation count |
|---|---|---|---|---|
| Sioux Rural Water System | Goodwin, Watertown | 4,000 | 0 | 0 |
| Clark Rural Water System | Clark, Florence | 2,130 | 0 | 34 |
| Estelline | Estelline | 768 | 0 | 82 |
| Castlewood | Castlewood | 627 | 0 | 67 |
| Clark Rural Water-kampeska | Clark, Florence | 578 | 0 | 42 |
| Bryant | Bryant | 450 | 0 | 4 |
| Lake Norden | Lake Norden | 424 | 0 | 6 |
| Hayti | Hayti | 375 | 0 | 11 |
| Mayfield Colony | County of Hamlin | 93 | 0 | 0 |
| Hazel | Hazel, Watertown | 91 | 0 | 0 |
| Claremont Colony | County of Hamlin | 40 | 0 | 0 |
| Poinsett Colony | County of Hamlin | 40 | 0 | 0 |
| Lake Poinsett Estates | Arlington | 36 | 0 | 0 |
| Lake Poinsett Campground | County of Hamlin | 25 | 0 | 0 |
| Dempster Cafe | Dempster | 25 | 0 | 0 |
| Trail's Edge | County of Hamlin | 25 | 0 | 0 |