Water Quality in O Fallon, IL: 2 Violations — Grade B
Grade B · Score 76/100 · 2 water systems · Updated 2026-05-03
O Fallon's water is mostly safe. Minor violations exist but are primarily monitoring-related.
Data: EPA Safe Drinking Water Information System (SDWIS) Last verified: 2026-05-03
Local water systems serving O Fallon, IL carry 2 EPA violations on record in the federal compliance database — documented events spanning categories from maximum contaminant level exceedances to monitoring requirements tracked by the national Safe Drinking Water program.
Water Quality by ZIP Code in O Fallon
Water quality varies across O Fallon's 1 ZIP codes. Check your specific ZIP for detailed contaminant data.
| ZIP Code | Grade | Score | Violations | Health | |
|---|---|---|---|---|---|
| 62269 | B | 76 | 2 | 0 | View report → |
Water Quality Overview
O Fallon, Illinois receives a water quality grade of B with an overall score of 76 out of 100, based on EPA compliance data from the Safe Drinking Water Information System (SDWIS).
The 2 water systems serving O Fallon have accumulated 2 EPA violations (all monitoring/reporting type). These violations are tracked across 1 ZIP codes serving approximately 47,183 people.
What Grade B Means
A grade of B indicates good compliance with EPA drinking water standards. While not perfect, O Fallon's water systems meet the vast majority of federal requirements. Minor violations may exist but typically relate to monitoring or reporting rather than health-based standards.
Lead Levels
The average 90th percentile lead level across O Fallon water systems is 0.0020 mg/L — within EPA limits. No ZIP codes exceed the EPA lead action level.
Radon Risk
O Fallon is in EPA Radon Zone 2 (Moderate risk). Testing is recommended, especially for homes with basements or ground-level living spaces.
Water Systems Serving O Fallon
O Fallon is served by 2 community water systems regulated under the Safe Drinking Water Act. These systems collectively serve approximately 47,183 people across 1 ZIP codes.
Each water system is identified by a Public Water System ID (PWSID) and is required to:
- Test for over 90 regulated contaminants on a regular schedule
- Report results to the EPA and state regulators
- Issue an annual Consumer Confidence Report (CCR) to all customers
- Take corrective action when violations occur
The EPA has taken 4 enforcement actions against water systems serving O Fallon. Enforcement actions range from informal compliance assistance to formal orders and penalties.
How to Check Your Water in O Fallon
Enter your ZIP code on ZipCheckup to see your specific water system data, including contaminant levels, violation history, and safety scores
Request your CCR — your water utility must provide an annual Consumer Confidence Report with detailed test results for all monitored contaminants
Get a home test — certified kits cost $20–$50 and test for lead, bacteria, and common contaminants. Professional lab tests ($150–$400) cover a broader panel
Consider filtration — NSF-certified filters can remove specific contaminants. Reverse osmosis removes the broadest range; activated carbon is effective for chlorine and many organics
Check for advisories — monitor your local utility website and local news for boil water advisories or system alerts
Contaminants Detected in O Fallon Water Systems
The following contaminants have been detected or caused violations across O Fallon's water systems:
| Contaminant | Category | MCL | Violations | ZIPs Affected | Health-Based |
|---|---|---|---|---|---|
| Surface Water Treatment Rule | Treatment Technique | N/A | 1 | 1 | No |
MCL = Maximum Contaminant Level (EPA enforceable standard). Health-based violations indicate levels that may pose direct health risks.
EPA Enforcement History
The EPA and state regulators have taken 4 enforcement actions against water systems serving O Fallon. Recent actions:
| Date | Action Type |
|---|---|
| 2022-07-11 | State Informal Action |
| 2022-06-30 | State Order Extension |
| 2022-06-14 | State Informal Action |
| 2022-06-14 | State Informal Enforcement |
Enforcement actions range from informal compliance assistance to formal orders and penalties. The most recent action was on 2022-07-11.
O Fallon vs. Nearby Illinois Cities
How O Fallon's water quality compares to similar cities in Illinois:
| City | Grade | Violations | Systems | Population |
|---|---|---|---|---|
| O Fallon | B | 2 | 2 | 47,183 |
| Rock Island | C | 15 | 2 | 46,818 |
| Glenview | D | 10 | 2 | 48,088 |
| Quincy | C | 6 | 4 | 48,254 |
Common Questions About O Fallon Water
These are the most common questions residents search for about water quality in O Fallon, Illinois:
Is O Fallon water hard or soft? Water hardness varies by source. O Fallon's 2 water systems use multiple sources. Check your ZIP code report for specific hardness data.
Can I drink O Fallon tap water? O Fallon's water receives a grade of B (76/100). No health-based violations have been recorded, but home testing is always recommended.
What is the best water filter for O Fallon? A NSF/ANSI 53-certified filter for lead removal is a good general choice. See our Water Filter Matcher for personalized recommendations.
O Fallon vs. Illinois Average
Understanding how O Fallon compares to the broader Illinois average helps contextualize your local water quality. Factors like water source, treatment methods, and infrastructure age all contribute to differences between cities in the same state.
To see how individual neighborhoods compare, check the ZIP code reports below — water quality can vary significantly even within O Fallon.
ZIP Codes in O Fallon
O Fallon spans 1 ZIP code. The ZIP with the lowest water quality score is 62269. Each ZIP code has its own water quality profile based on the specific water system serving that area. Check each ZIP code for detailed contaminant data, violation history, and system information.
Data Sources
- Water quality: EPA Safe Drinking Water Information System (SDWIS)
- Lead/copper: EPA Lead and Copper Rule sampling data
- Radon: EPA Map of Radon Zones
- Enforcement: EPA ECHO database
- Filter recommendations: NSF/ANSI certified products
Updated daily.
Frequently Asked Questions
Your Water is Safe — Here's How to Keep It That Way
Grade B is excellent news. Here's what proactive homeowners do to maintain water quality:
Annual Water Testing
EPA recommends annual testing even with clean water. Home test kits: $20-$50. Catches changes before they become problems.
Maintenance Filtration
A basic carbon filter removes chlorine taste and catches emerging contaminants like PFAS that aren't yet fully regulated.
Plumbing Check
Even safe city water picks up lead from home pipes. If your home was built before 1986, a one-time pipe inspection is recommended.