Water quality in O'Fallon, Missouri
O'Fallon is in St. Charles County. 55 active public water systems serve the county; 34 had an EPA violation in the past three years.
Most likely your provider
Your location is within the outer bounds of this system's EPA service area.
Other community water systems in St. Charles County
18 systems, nearest first| System | Serves | Status | Rules violated, 3 yr | Distance |
|---|---|---|---|---|
| ST Paul PWS |
1,700 | 1 | 2.7 mi | |
| ST Peters PWS St. Peters |
52,575 | 0 | 5.8 mi | |
| Wentzville PWS Wentzville |
41,784 | 1 | 7.7 mi | |
| Weldon Spring Heights Village PWS Weldon Spr Hght |
100 | 0 | 8.2 mi | |
| Ecm Water & Sewer Authority Flint Hill Flint Hill |
469 | 0 | 9.4 mi | |
| ST Charles PWS St. Charles |
78,961 | 1 | 10.4 mi | |
| ST Charles County Pwsd 2 |
100,587 | 1 | 10.6 mi | |
| Prairie View Acres Subd |
135 | 2 | 10.8 mi | |
| Country Estates |
50 | 2 | 11.6 mi | |
| MO American Jaxson Foristell |
535 | 0 | 12.3 mi | |
| Big Country Acres Subdivision |
90 | 3 | 12.3 mi | |
| ST Charles Pwsd 2 Foristell Foristell |
550 | 1 | 14.1 mi | |
| ST Charles CO Pwsd 2 Augusta |
881 | 0 | 18.1 mi | |
| MO American ST Louis ST Charles Counties |
1,111,000 | 0 | 18.5 mi | |
| Portage Des Sioux PWS Portagedessioux |
345 | 1 | 20.8 mi | |
| ST Charles CO Pwsd 2 Sumac Ridge |
103 | 1 | — | |
| Tara Oaks Manor Assn |
100 | 1 | — | |
| Confluence Rivers Stone Ridge Meadows |
60 | 1 | — |
Non-community systems in St. Charles County (36: schools, campgrounds, workplaces, restaurants)
These systems serve places you visit rather than homes.
About this data
Water systems are matched to St. Charles County, nearest to O'Fallon first. Your exact provider depends on your address and connection; the largest community water system in a county is usually the city or town utility. Distances are measured to the centre of the service area EPA publishes for the system or, for systems without one, to the centre of the first town EPA lists the system as serving, from Census Bureau place files.
Town locations and ZIP code areas come from U.S. Census Bureau 2020 files.
Source: the U.S. EPA's Enforcement and Compliance History Online system (ECHO), which publishes the federal Safe Drinking Water Information System. EPA's terms and values are shown as published. The Missouri records are from EPA's data refresh of Oct 7, 2026; EPA refreshes this data quarterly, and states report to EPA with a lag of three to six months, so the newest violations may not appear yet. Retrieved from ECHO on Oct 11, 2026.