F3/100
O FALLON — Water Quality Report 2026
Serving 46,603 people · Illinois
Water Source
Purchased Surface Water
County
—
System ID
IL1631100
Violations
26
Contaminant Test Results
1 contaminant above EPA health goals
| Contaminant | Detected | Limit (MCL) | Status |
|---|---|---|---|
chlorate | 250.00 µg/L | — | Above Goal |
EPA Violation History
No violations in the past 5 years
Full EPA compliance since 2007.
Understanding violation severity
Tier 1Urgent health risk. Utility must notify all customers within 24 hours.Tier 2Important health or treatment issue. Customers notified within 30 days.Tier 3Administrative or monitoring issue. Reported in the annual water quality report.
Source: EPA Safe Drinking Water Information System (SDWIS) · Updated quarterly
Frequently Asked Questions About O FALLON
Is O FALLON water safe to drink?
O FALLON water receives a grade of F (3/100), which is considered failing. 0 contaminant(s) exceed EPA legal limits and 26 violation(s) are on record. Customers may want to consider using a water filter.
What contaminants has O FALLON detected?
69 contaminants were tested in O FALLON's water. Notable contaminants include chlorate. No contaminants exceed EPA legal limits. 1 exceed EPA health goals (MCLGs).
Does O FALLON have any EPA violations?
Yes, O FALLON has 26 EPA violation(s) on record, with the most recent in 2007. Violation types include MR, MCL, TT. 17 are health-based violations.
How many people does O FALLON serve?
O FALLON serves approximately 46,603 people, Illinois. The system provides water to 1 community: O Fallon.
What type of water does O FALLON provide?
O FALLON sources its water from purchased surface water. Surface water comes from rivers, lakes, or reservoirs and typically requires more extensive treatment. The utility's system ID is IL1631100.
How does O FALLON compare to other utilities in Illinois?
O FALLON scores 3/100 with a grade of F (failing). This score suggests significant water quality concerns relative to other utilities. Visit our Illinois state page for a full comparison of water systems.