Compliance record
Formal violations the EPA has on file for this supplier. A health-based violation means a contaminant limit or a required treatment was breached; the rest are monitoring or reporting failures — still violations, but not a measured health risk.
| Violation | Type | Status | Period |
|---|---|---|---|
| MCL | Health-based | Archived | 1991-06-25 → 1991-07-24 |
| MR | Monitoring | Resolved | 2025-06-01 → 2025-06-30 |
| MR | Monitoring | Resolved | 2025-06-01 → 2025-06-30 |
| MR | Monitoring | Resolved | 2025-06-01 → 2025-06-30 |
PFAS detected
Other contaminants detected
| Contaminant | Level vs EPA limit | Detection rate | Source | Period |
|---|---|---|---|---|
| Copper | 158.8 µg/L 12% of the EPA limit 1300 µg/L
worst single sample: 577 µg/L | 100/100 | SYR4 | 2013–2019 |
| Nitrate-Nitrite | 380.5 µg/L 3.8% of the EPA limit 10000 µg/L
worst single sample: 560 µg/L | 70/78 | SYR4 | 2012–2019 |
| Lead | 3.7015 µg/L 25% of the EPA limit 15 µg/L
worst single sample: 4.56 µg/L | 40/100 | SYR4 | 2013–2019 |
| Lead | 0.0015 mg/L 9.9% of the EPA limit 0.0150 mg/L | 23/23 | LCR | 2025 |
| Dibromochloromethane | 2.586 µg/L No EPA limit set
worst single sample: 2.82 µg/L | 19/24 | SYR4 | 2012–2019 |
| Bromodichloromethane | 3.712 µg/L No EPA limit set
worst single sample: 4.52 µg/L | 17/24 | SYR4 | 2012–2019 |
| Chloroform | 3.6225 µg/L No EPA limit set
worst single sample: 4.98 µg/L | 16/24 | SYR4 | 2012–2019 |
| TTHM | 10.74 µg/L 13% of the EPA limit 80 µg/L
worst single sample: 12.3 µg/L | 14/14 | SYR4 | 2012–2019 |
| Bromoform | 1.5425 µg/L No EPA limit set
worst single sample: 1.57 µg/L | 12/24 | SYR4 | 2012–2019 |
| Barium | 108.2 µg/L 5.4% of the EPA limit 2000 µg/L
worst single sample: 110 µg/L | 10/10 | SYR4 | 2014–2017 |
| Chromium | 7.444 µg/L 7.4% of the EPA limit 100 µg/L
worst single sample: 7.48 µg/L | 10/22 | SYR4 | 2013–2017 |
| Lithium | 71.3 µg/L No EPA limit set | 10/12 | UCMR-5 | 2025 |
| Fluoride | 1276 µg/L 32% of the EPA limit 4000 µg/L
worst single sample: 1280 µg/L | 9/10 | SYR4 | 2014–2017 |
| Arsenic | 2.269 µg/L 23% of the EPA limit 10 µg/L
worst single sample: 2.32 µg/L | 7/10 | SYR4 | 2014–2017 |
| Combined Radium (-226 And -228) | 5.14 pCi/L 103% of the EPA limit, at the 95th percentile of samples — 5 pCi/L
worst single sample: 5.8 pCi/L | 7/12 | SYR4 | 2013–2019 |
| Trichloroacetic Acid | 2.474 µg/L No EPA limit set
worst single sample: 2.78 µg/L | 7/14 | SYR4 | 2012–2019 |
| Dichloroacetic Acid | 2.782 µg/L No EPA limit set
worst single sample: 2.79 µg/L | 5/14 | SYR4 | 2012–2019 |
| Monobromoacetic Acid | 6.7325 µg/L No EPA limit set
worst single sample: 6.84 µg/L | 2/14 | SYR4 | 2012–2019 |
| Dibromoacetic Acid | 1.5 µg/L No EPA limit set | 1/14 | SYR4 | 2012–2019 |
| Selenium | 11 µg/L 22% of the EPA limit 50 µg/L | 1/10 | SYR4 | 2014–2017 |
77 contaminants tested, none detected
Utility contact
Frequently asked questions about Ofallon
Is Ofallon tap water safe to drink?
EPA monitoring detected 22 contaminants in Ofallon's water. A detection isn't the same as a violation — most levels are within federal limits. See each level and source above, and the utility's annual Consumer Confidence Report for its official compliance status.
What contaminants were detected in Ofallon's water?
EPA monitoring detected Copper, Nitrate-Nitrite, Lead, Lead, Dibromochloromethane, and others. The full list with the level and data source for each is above.
How many people does Ofallon serve?
Ofallon reports serving 32,515 people in Missouri, per its EPA record.
Has Ofallon had any water quality violations?
The EPA has 4 violations on file for Ofallon, of which 1 is health-based (a contaminant limit or required treatment was breached) and 0 remain open. The rest are monitoring or reporting failures.
Where does this data come from?
Every figure is official EPA drinking-water monitoring — the Lead & Copper Rule, the UCMR-5 nationwide testing program, and the EPA Six-Year Review — not our own testing. Each number is labelled with its source and period.