O Fallon
PWSID IL1631100 · O'fallon, Illinois · serves 46,603 people · surface water source
B
Good
PFAS test results (EPA UCMR 5)
| Contaminant | Result | Federal limit (MCL) | Sampled |
|---|---|---|---|
| PFBA | 13 ppt | — | 2/7/2024 |
| PFBA | 12.1 ppt | — | 8/7/2024 |
| PFBA | 11.9 ppt | — | 5/8/2024 |
| PFBA | 9.9 ppt | — | 11/7/2024 |
ppt = parts per trillion (ng/L). Rows highlighted red meet or exceed the 2024 federal limit.
Violation history
| Date | Violation | Type | Health-based | Status |
|---|---|---|---|---|
| 2026-01-01 | TTHM | MR | No | Resolved |
| 2026-01-01 | Total Haloacetic Acids (HAA5) | MR | No | Resolved |