Ofallon Public Water System
EPA ID: MO6010588 · 32,515 people served · 3 ZIP codes
ZipCheckup's reading of EPA records for Ofallon Public Water System (MO6010588): 1 violation on record since 2021. While 1 violation did appear in Ofallon Public Water System's monitoring record, none is listed as unresolved; the utility serves approximately 32,515 residents. A closed violation record does not by itself establish compliance with every current EPA standard.
Data: EPA SDWIS
Service Area Map
Coverage area for Ofallon Public Water System Source: EPA SDWIS service area boundaries.
Service area boundary
Demographics of ZIP Codes Served
The ZIP codes associated with Ofallon Public Water System have a median household income of $98,237 and about 179,745 residents live in those ZIP codes (Census; not the number of people this system supplies).
🌊 Where Does Your Water Come From?
Ofallon Public Water System's water is drawn from rivers, lakes, or reservoirs. Surface water sources are more exposed to agricultural runoff, stormwater, and upstream discharges, but they typically receive more intensive treatment before reaching your tap.
Superfund Proximity Note: This service area ranks in the 70th percentile nationally for proximity to Superfund (NPL) sites.
Infrastructure Risk
PFAS in ZIP Codes This System Serves
PFAS ("forever chemicals") have been reported in samples from water systems associated with the ZIP codes in this system's area. These results can come from other water systems serving the same ZIP codes; check the UCMR5 section for any results reported for this system. 7 detections recorded. 1 detection is above the level of a federal PFAS MCL (4 ppt for PFOA and PFOS), with compliance required from 2029.
Comparable Water Systems
Similar-sized systems in Missouri
Estimated Remediation Costs
Average estimated costs across ZIP codes served by this system
Based on national averages for common remediation projects. Actual costs vary by property. Only issues flagged by EPA, FEMA, or state data for each ZIP code are included.
System Overview
Ofallon Public Water System (EPA ID: MO6010588) is a community water system in Missouri that serves approximately 32,515 people from surface water sources.
This system provides water to 3 ZIP codes across 3 communities.
Violation History
Status breakdown for accepted records with record years 2021-2026: 1 resolved, 0 archived, 0 addressed, and 0 unaddressed. Under this source contract, current noncompliance is the sum of addressed and unaddressed records. Archived and resolved records are excluded from current noncompliance.
Recent Violations
| Date | Contaminant | Type | Status |
|---|---|---|---|
| June 1, 2025 | Groundwater Rule | Non-health-based | Resolved |
Contaminants Detected
The following contaminants have been flagged in EPA records for this water system:
| Contaminant | Category | Violations | Health-Based |
|---|---|---|---|
| Groundwater Rule | Other Violation | 1 | No |
Lead & Copper
EPA Lead and Copper Rule evidence attributed directly to this water system:
| Lead Level | Exceeds Action Level | Sample Date |
|---|---|---|
| 0.0015 mg/L | No | 2025-12-31 |
No copper action-level exceedance record appears for this PWSID in the accepted LCR snapshot. This does not establish a clean copper measurement.
Need help with your water quality?
Typical cost: Water test: typically $20–$50 (DIY kit) · Professional inspection: $150–$400
Find the Right Water FilterFree tip: Ask your water utility whether running cold water for 2 minutes is enough to flush your plumbing before drinking.
ZIP Codes Served
Coverage: Service area ZIP codes sourced from EPA Community Water System Service Area Boundaries v3 (March 2026 release). These ZIPs reflect the actual deployment footprint recorded by MO or modeled from parcel and building-footprint data.
Data Sources
This report uses public data from the EPA Safe Drinking Water Information System (SDWIS). View available EPA compliance records for Ofallon Public Water System (MO6010588) on EPA.gov.
Frequently Asked Questions
Is Ofallon Public Water System water safe to drink?
The accepted 2026Q2 ECHO snapshot shows no current noncompliance for Ofallon Public Water System; its 1 accepted 2021-2026 record are resolved or archived. Historical compliance status does not establish conditions at a specific tap.
How many people does Ofallon Public Water System serve?
Ofallon Public Water System serves approximately 32,515 people across 3 ZIP codes in Missouri.
Where does Ofallon Public Water System get its water?
The primary water source is surface water.
Federal UCMR5 PFAS Monitoring: Detected
This water system was tested under the federal EPA Unregulated Contaminant Monitoring Rule (UCMR5). PFAS compounds were detected; the table compares each one with the EPA MCL where one exists (April 2024 rule, compliance required from 2029) and with this state's enforceable standard where one exists.
EPA's April 2024 PFAS rule sets MCLs of 4 ppt for PFOA and PFOS and 10 ppt for PFHxS, PFNA and HFPO-DA (GenX); water systems must comply from 2029. Other PFAS compounds have no individual federal MCL. A state standard is shown only where this system's state has its own enforceable PFAS limit. Detection results are EPA UCMR5 samples, not a measurement at your tap.
Source: U.S. EPA UCMR5 (Unregulated Contaminant Monitoring Rule, 5th cycle) — per-system federal sampling, 2023–2025. EPA UCMR5 monitoring program →
How Water Systems Appear in Rankings
Water systems are evaluated by violation history, contaminant detections, and service population. Larger systems with more service connections appear in more rankings.
- #37 / 50 Highest Exposure Burden (Missouri)
Frequently Asked Questions
How to cite this page
ZipCheckup. (n.d.). Ofallon Public Water System (MO): 1 EPA Violation. https://zipcheckup.com/water-system/mo6010588/
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title = {{Ofallon Public Water System (MO): 1 EPA Violation}},
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url = {https://zipcheckup.com/water-system/mo6010588/}
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What You Can Do
Test your water
Home test kits can detect lead, bacteria, and other contaminants at your tap. Find the right filter →
Check your specific ZIP code
Water quality can vary within a system. View nearest ZIP report →
Contact your utility
Ofallon Public Water System (EPA ID: MO6010588) - request the latest Consumer Confidence Report or ask about specific contaminants.