We found 32 public water systems in St. Clair county (ordered by population size).
| Name | Areas served | Population served | Contaminant count | Violation count |
|---|---|---|---|---|
| Harry S Truman Pwsd 2 | Clinton | 2,700 | 0 | 8 |
| H Roe Bartle Scout Reservation | County of St. Clair | 1,800 | 0 | 5 |
| Appleton City | Appleton City | 1,518 | 0 | 41 |
| Osceola | Osceola | 947 | 0 | 9 |
| Collins Pilot 385 | County of St. Clair | 735 | 0 | 43 |
| Lowry City | Lowry City | 630 | 0 | 45 |
| Osceola Public School | County of St. Clair | 575 | 0 | 6 |
| Osceola Cheese Company | County of St. Clair | 500 | 0 | 9 |
| Lakeland R-iii High School | County of St. Clair | 300 | 0 | 0 |
| Osceola Cheese | Osceola Cheese | 212 | 0 | 0 |
| Collins | Collins | 156 | 0 | 4 |
| Truman-crowes Crossing | Warsaw | 150 | 0 | 0 |
| Sugarfoot Barbeque | Osceola | 128 | 0 | 3 |
| United Producers Inc | County of St. Clair | 100 | 0 | 0 |
| Countryside Trading Post | County of St. Clair | 100 | 0 | 0 |
| Scotts Iconium Store | County of St. Clair | 100 | 0 | 0 |
| Osceola Standard Station | Osceola Standar | 100 | 0 | 0 |
| Chuck Wagon Cafe | Chuck Wagon Caf | 100 | 0 | 0 |
| Usace Truman Talley Bend Pua | Warsaw | 100 | 0 | 0 |
| Roscoe C 1 Elem School | County of St. Clair | 90 | 0 | 0 |
| Truman-brush Creek | Warsaw | 75 | 0 | 0 |
| Kappaws Kids | County of St. Clair | 51 | 0 | 0 |
| Twin Oaks Harbor | County of St. Clair | 50 | 0 | 0 |
| Usace Truman Berry Bend South | County of St. Clair | 50 | 0 | 0 |
| Country Cafe | Country Cafe | 50 | 0 | 0 |
| Wildflower Inn | County of St. Clair | 32 | 0 | 0 |
| First Baptist Church | First Baptist | 25 | 0 | 0 |
| Coon Creek Baptist Church | Coon Creek Bapt | 25 | 0 | 0 |
| Ricochet Ridge Subdivision | County of St. Clair | 25 | 0 | 0 |
| Round Prairie Baptist Church | County of St. Clair | 25 | 0 | 0 |
| Krebs Mobile Home Living | County of St. Clair | 21 | 0 | 0 |
| Woodland Acres | Lowry City | 0 | 0 | 0 |