Lead in O Fallon, MO Drinking Water
Lead data for O Fallon, Missouri · 139,544 residents · 2 ZIP codes
In O Fallon, Missouri, Lead has been detected in the public water supply — a contaminant that health agencies track because of documented effects associated with prolonged exposure at elevated concentrations.
Data: EPA SDWIS, CCR Reports, ECHO Last verified: 2026-05-14
Lead in O Fallon Tap Water
Lead has been detected in O Fallon, Missouri drinking water at a maximum level of 1.1 ppb — below the EPA action level of 15 ppb (action level).
This analysis covers 139,544 residents across 2 ZIP codes in O Fallon.
O Fallon's overall water quality grade is C (69/100).
Is Lead in O Fallon Water Safe?
Lead was detected in O Fallon water but currently falls within EPA limits. However, some health organizations argue the EPA action level may not be protective enough — the CDC states there is no safe level of lead for children.
If you are concerned, a reverse osmosis or nsf 53 carbon block filter can reduce lead levels further.
Lead Levels by ZIP Code
| ZIP Code | Lead Level | EPA Limit | Status |
|---|---|---|---|
| 63366 | 1.1 ppb | 15 ppb (action level) | OK |
| 63368 | 1.1 ppb | 15 ppb (action level) | OK |
Average lead level across O Fallon: 1.1 ppb
Health Effects of Lead
- Brain development delays and reduced IQ in children
- Behavioral problems and learning disabilities
- High blood pressure and kidney damage in adults
- Increased risk of premature birth in pregnant women
Health risk severity: High. Governed by the Lead and Copper Rule Revisions (LCRR/LCRI).
How Lead Gets Into Drinking Water
- Corrosion of lead service lines (pipes connecting water main to home)
- Lead solder in copper plumbing joints (pre-1986 homes)
- Brass fixtures and faucets manufactured before 2014
- Stagnant water that sits in lead-containing pipes overnight
What to Do About Lead in O Fallon Water
- Install an NSF 53 or NSF 58 certified filter at kitchen sink
- Run cold water for 30 seconds before using for drinking or cooking
- Use cold water only for cooking and preparing formula
- Consider whole-home reverse osmosis if lead service line is present
Look for filters certified under NSF 53 / NSF 58 for lead removal.