We found 28 public water systems in Calhoun county (ordered by population size).
| Name | Areas served | Population served | Contaminant count | Violation count |
|---|---|---|---|---|
| Lake City Water Supply | Lake City | 1,727 | 0 | 45 |
| Rockwell City Water Supply | Rockwell City | 1,714 | 0 | 4 |
| Manson Water Supply | Manson | 1,692 | 0 | 28 |
| Pomeroy Water Supply | Pomeroy | 670 | 0 | 4 |
| Sparkys One Stop Calhoun | Rockwell City | 400 | 0 | 1 |
| Farnhamville Water Supply | Farnhamville | 382 | 0 | 4 |
| Lohrville Water Supply | Lohrville | 368 | 0 | 8 |
| Lytton Water Department | Lytton | 320 | 0 | 13 |
| Twin Lakes Utilities | Rockwell City | 300 | 0 | 13 |
| Prairie Valley Community School | Farnhamville | 300 | 0 | 0 |
| Somers Water Works | Somers | 118 | 0 | 0 |
| Knierim Water Supply | Knierim | 60 | 0 | 0 |
| Cottonwood Supper Club | County of Calhoun | 60 | 0 | 0 |
| Rinard Water Supply | Rinard | 57 | 0 | 0 |
| Knoke Corral | County of Calhoun | 50 | 0 | 0 |
| Harvest Acres, Inc. | Rockwell City | 42 | 0 | 0 |
| Jolley Water Supply | Jolley | 41 | 0 | 0 |
| Twin Lakes Bible Camp | County of Calhoun | 40 | 0 | 0 |
| Twin Lakes Golf Club | Rockwell City | 39 | 0 | 0 |
| YETTER MUNICIPAL WATER SUPPLY | Yetter | 34 | 0 | 0 |
| Leit's Locker Plant | County of Calhoun | 30 | 0 | 0 |
| Dx Station And Restaurant | County of Calhoun | 30 | 0 | 0 |
| Twin Lakes Trailer Court | County of Calhoun | 30 | 0 | 0 |
| Kelley's Kafe | County of Calhoun | 25 | 0 | 0 |
| Twin Lakes State Park | County of Calhoun | 25 | 0 | 0 |
| Rainbow Bend Acc-calhoun Cons | County of Calhoun | 25 | 0 | 0 |
| University Forty Pk-calhoun Co | County of Calhoun | 25 | 0 | 0 |
| Hickory Grove Pk-calhoun Consr | County of Calhoun | 25 | 0 | 0 |