O Fallon

Water Quality Snapshot: O Fallon

O Fallon is a local-owned community water system that delivers drinking water to 46,603 residents in O'Fallon, Illinois (St. Clair County) through 18,497 service connections. Its water is drawn from surface water sources. EPA's Safe Drinking Water Information System records 102 total violations for this system , of which 44 (43%) are health-based, meaning a contaminant exceeded an EPA Maximum Contaminant Level or a required treatment technique failed. A further 24 monitoring and reporting violations are on file. The most recent violation on record dates to 2007.

The most frequently cited contaminant at this system is Coliform (TCR), recorded in 42 violations (MCL, health-based). Under EPA's UCMR5 PFAS monitoring program, 1 PFAS compound was detected in samples collected from this system, with a maximum reported concentration of 13 ppt (parts per trillion). PFAS are persistent synthetic chemicals linked to health effects at very low exposure levels.

Across Illinois, EPA tracks 5,117 public water systems serving 12,576,876 people, with 355,322 cumulative violations and 52,932 health-based violations on record. About 81% of systems in the state carry at least one violation, and state-wide the average per system is 69.4 violations. Statewide, 199 of 487 UCMR5-tested systems have reported PFAS detections (40.9%).

O Fallon's 102 violations sit above the Illinois average.

All figures above are sourced directly from EPA SDWIS and UCMR5 public data releases and are updated as EPA publishes new reporting cycles.