MyCleanWater

O Fallon, Missouri Water Quality Report

Water quality data for 12 water systems serving 142,677 people.

85
Good
out of 100

Water Source

12
Water Systems
143K
People Served
Surface water, Ground water
Water Source

Detected Contaminants

ContaminantDetected LevelEPA Limit (MCL)Health Guideline% of LimitStatus
lithium71.3 No federal limit10.0 ug/L(EPA/USGS HBSL)
713%
Above guideline
PFBA0.006 No federal limit1000.0 ug/L(EWG)
0%
Below guideline
PFPeA0.003 No federal limit1000.0 ug/L(EWG)
0%
Below guideline

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Compliance & Violations

Active Violations (84)

71

Jul 1, 2025

minor

4G

Oct 17, 2024

minor

4G

Oct 17, 2024

minor

4G

Oct 17, 2024

minor

66

Oct 1, 2024

moderate

71

Jul 1, 2024

minor

Violation

Unknown

minor

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minor

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minor

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minor

Resolved Violations (244)

3A

Jul 1, 2025 — Jul 31, 2025

minor

3A

Jul 1, 2025 — Jul 31, 2025

minor

3A

Jul 1, 2025 — Jul 31, 2025

minor

3A

Jul 1, 2025 — Jul 31, 2025

minor

3A

Jun 1, 2025 — Jun 30, 2025

minor

+ 239 more resolved violations

Frequently Asked Questions

Is O Fallon tap water safe to drink?

O Fallon's water meets all EPA maximum contaminant levels. However, 3 contaminants were detected at various levels. Some residents may prefer additional filtration for peace of mind.

What contaminants are in O Fallon tap water?

3 contaminants have been detected in O Fallon's water supply across 12 water systems. See the full contaminant table above for details.

How can I improve my water quality in O Fallon?

Install a water filter rated for the specific contaminants found in O Fallon's water. See our filter recommendations above. You can also request your utility's Consumer Confidence Report for the most current test results.

Does O Fallon have any water quality violations?

Yes, O Fallon currently has 84 active violations. See the violations section above for details.