We found 11 public water systems that could serve the same population as Lake St John Waterworks District 1 (ordered by population size).
| Name | Areas served | Population served | Contaminant count | Violation count |
|---|---|---|---|---|
| Concordia Waterworks District 1 | County of Concordia Parish | 6,921 | 0 | 2 |
| City Of Vidalia Water System | County of Concordia Parish | 6,354 | 0 | 8 |
| Monterey Rural Water System Inc | County of Concordia Parish | 5,250 | 0 | 4 |
| Town Of Ferriday Water System | County of Concordia Parish | 4,193 | 0 | 139 |
| Town Of Clayton Water System | County of Concordia Parish | 723 | 0 | 50 |
| Town Of Ridgecrest Water Supply | County of Concordia Parish | 683 | 0 | 27 |
| Red Gum Waterworks Inc | County of Concordia Parish | 495 | 0 | 0 |
| North Lake St John Water System | County of Concordia Parish | 90 | 0 | 0 |
| Donalds Camper Village | County of Concordia Parish | 64 | 0 | 0 |
| La Hydroelectric Limited Partnership | County of Concordia Parish | 30 | 0 | 0 |
| Baileys Trailer Park | County of Concordia Parish | 16 | 0 | 0 |