Is O'Fallon, IL Tap Water Safe to Drink?
O'Fallon tap water meets federal Safe Drinking Water Act standards but 1 of 1 ZIP code show detections above EPA health guidelines, primarily for lithium. A certified filter is recommended for households that want an additional layer of protection.
Where Does O'Fallon Get Its Water?
Water in O'Fallon, IL is provided by 4 public water systems: TRITOWNSHIP WATER DISTRICT, CASEYVILLE, IL AMERICAN-EAST ST LOUIS and O FALLON.
How Is O'Fallon Tap Water Treated?
Treated water is disinfected using free chlorine and calcium hypochlorite. Treatment includes conventional treatment (coagulation, flocculation, and filtration).
What's in O'Fallon Tap Water?
The following contaminants were detected most frequently in O'Fallon public water systems. 1 of 1 ZIP codes showed detections above EPA health guidelines.
| Contaminant | Peak detected | EPA guideline | ZIPs detected | Status |
|---|---|---|---|---|
| lithium | 13.1 µg/L | 10 µg/L | 1 ZIP | Above guideline |
| PFTrDA | 0.007 µg/L | — | 0 ZIPs | Within guideline |
| PFBA | 0.005 µg/L | — | 0 ZIPs | Within guideline |
| 6:2 FTS | 0.005 µg/L | — | 0 ZIPs | Within guideline |
| 11Cl-PF3OUdS | 0.005 µg/L | — | 0 ZIPs | Within guideline |
Health Risk Profile for O'Fallon
Based on EPA monitoring data, 1 of 1 ZIP codes in O'Fallon have recorded detections above EPA health guidelines. Sensitive populations such as infants, pregnant individuals, and those with weakened immune systems may benefit from an additional layer of protection such as a certified point-of-use filter.
Best Filters for PFAS Water Profile
PFAS compounds are detected in this water supply. A reverse osmosis (RO) system or an activated-carbon filter specifically certified under NSF/ANSI P473 is required for reliable PFAS reduction. Standard pitcher and faucet filters without P473 certification do not remove PFAS.
8-stage tankless RO system certified to NSF/ANSI 58, reduces 1,000+ contaminants including PFAS, lead, arsenic, fluoride, and nitrates.
NSF-certified dual-layer filtration reduces 70+ contaminants including PFAS, lead, chlorine, microplastics, and bacteria.
See recommendations matched to your exact address: choose your ZIP code below.
Frequently Asked Questions about O'Fallon Tap Water
Is O'Fallon tap water safe to drink?
O'Fallon tap water meets Safe Drinking Water Act requirements but 1 of 1 ZIP codes show contaminant levels above EPA health-based guidelines. A certified point-of-use filter adds an extra layer of protection.
What contaminants are in O'Fallon tap water?
The most commonly detected contaminants in O'Fallon water systems include: lithium, PFTrDA, PFBA. See the ZIP-level reports for exact measurements and EPA guideline comparisons.
Where does O'Fallon get its drinking water?
O'Fallon receives water from 4 public water systems, including TRITOWNSHIP WATER DISTRICT.
Do I need a water filter in O'Fallon?
If your ZIP code is among those with detections above EPA health guidelines, choose a filter certified for the specific contaminants shown in your ZIP report. Reverse osmosis is generally the broadest option for PFAS, lithium, and many other dissolved contaminants.
How often is O'Fallon tap water tested?
Public water systems in O'Fallon are required by the EPA to test for regulated contaminants on schedules ranging from daily (for microbials and disinfectants) to annual or triennial (for many chemical contaminants). Results are published in annual Consumer Confidence Reports (CCRs). The data on this page reflects the most recent available EPA monitoring results, with the latest sample date of 2025-11-04.
Tap water reports by ZIP in O'Fallon
- 62269 - O'Fallon tap water report Higher concern
Water utilities serving O'Fallon, IL
Service area boundaries are approximate and based on state filings or modeled estimates. Contact your utility to confirm exact service at a specific address.
- CASEYVILLEAction advised
- IL AMERICAN-EAST ST LOUISAction advised
- O FALLONLooks OK
- TRITOWNSHIP WATER DISTRICTLooks OK
Also covers / overlaps with
- Caseyville, IL · Township
- Shiloh, IL
- Shiloh Valley, IL · Township