We found 16 public water systems that could serve the same population as Dairy Castle (ordered by population size).
| Name | Areas served | Population served | Contaminant count | Violation count |
|---|---|---|---|---|
| Hannibal | Hannibal | 17,916 | 46 | 41 |
| Marion Co Pwsd 1 | Philadelphia | 4,900 | 0 | 0 |
| Palmyra | Palmyra | 3,595 | 0 | 0 |
| American Cyanamid Co | American Cyanam | 550 | 0 | 0 |
| Smittys Truck Stop | Smittys Truck S | 500 | 0 | 0 |
| Interstate Car Auction | County of Marion | 500 | 0 | 0 |
| Burlington-northern Railro | Burlington Rr | 200 | 0 | 0 |
| Mississippi Grill | County of Marion | 200 | 0 | 0 |
| Knapheide Mfg. Company | West Quincy | 150 | 0 | 0 |
| Bay View Camper Park | Bay View Park | 60 | 0 | 0 |
| Farmers-traders Comm Co., I | Livestock Markt | 38 | 0 | 0 |
| Bleigh Construction | Hannibal | 25 | 0 | 0 |
| Fiesta Motel | Fiesta Motel | 25 | 0 | 0 |
| Minor Mobile Home Park | Minor Mhp | 25 | 0 | 0 |
| Ayers Oil Co | Ayers Oil Co | 25 | 0 | 0 |
| Skyview Ranch Campground | Skyview Ranch | 20 | 0 | 0 |