Mason City
EPA ID: IL1250350 · 2,393 people served · 1 ZIP code
ZipCheckup's reading of EPA records for Mason City (IL1250350): 1 violation recorded with unresolved status in the SDWIS data used. Looking at the EPA enforcement file for Mason City, 1 violation is listed as unresolved as of its reporting date; the utility's service area includes approximately 2,393 people.
Data: EPA SDWIS
Service Area Map
Coverage area for Mason City Source: EPA SDWIS service area boundaries.
Service area boundary
Demographics of ZIP Codes Served
The ZIP codes associated with Mason City have a median household income of $71,012 and about 2,848 residents live in those ZIP codes (Census; not the number of people this system supplies). Approximately 87% of housing stock was built before 1986, which increases the likelihood of lead service lines and older plumbing.
Environmental Justice Note: On average, 67% of census tracts in the counties mapped to this service area are designated disadvantaged by the federal Climate and Economic Justice Screening Tool (CEJST, 2022 version). Communities with higher disadvantaged populations often face disproportionate environmental and health burdens, including aging water infrastructure and limited resources for remediation.
💧 Where Does Your Water Come From?
Mason City's water is classified in EPA records as a groundwater source. Groundwater is naturally filtered through rock and soil, but it can be vulnerable to PFAS contamination, nitrates from agriculture, and industrial chemicals that seep into the water table.
Infrastructure Risk
Comparable Water Systems
Similar-sized systems in Illinois
System Overview
Mason City (EPA ID: IL1250350) is a community water system in Illinois that serves approximately 2,393 people from groundwater sources.
This system serves ZIP code 62664 in Mason City.
Violation History
Status breakdown for accepted records with record years 2021-2026: 0 resolved, 0 archived, 0 addressed, and 1 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 |
|---|---|---|---|
| July 2, 2025 | LEAD AND COPPER RULE REVISIONS | Non-health-based | Unaddressed (current) |
Contaminants Detected
The following contaminants have been flagged in EPA records for this water system:
| Contaminant | Category | Violations | Health-Based |
|---|---|---|---|
| LEAD AND COPPER RULE REVISIONS | Monitoring & Reporting | 1 | No |
Lead & Copper
EPA Lead and Copper Rule evidence attributed directly to this water system:
| Lead Level | Exceeds Action Level | Sample Date |
|---|---|---|
| Below the reporting limit | 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.
Radon Risk in Service Area
1 of 1 ZIP records with known zones is in EPA Radon Zone 1.
The EPA recommends testing all homes regardless of radon zone. County radon zones cannot replace an in-home radon test.
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 IL or modeled from parcel and building-footprint data.
- 62664 - Mason City
Data Sources
This report uses public data from the EPA Safe Drinking Water Information System (SDWIS). View available EPA compliance records for Mason City (IL1250350) on EPA.gov.
Frequently Asked Questions
Is Mason City water safe to drink?
The accepted 2026Q2 ECHO snapshot shows 1 current noncompliance record and zero current records classified as health-based. That classification is not a property-specific water test or safety guarantee.
How many people does Mason City serve?
Mason City serves approximately 2,393 people across 1 ZIP code in Illinois.
Where does Mason City get its water?
The primary water source is groundwater.
Frequently Asked Questions
How to cite this page
ZipCheckup. (n.d.). Mason City (IL): 1 EPA Violation. https://zipcheckup.com/water-system/il1250350/
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author = {{ZipCheckup}},
title = {{Mason City (IL): 1 EPA Violation}},
year = {n.d.},
url = {https://zipcheckup.com/water-system/il1250350/}
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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
Mason City (EPA ID: IL1250350) - request the latest Consumer Confidence Report or ask about specific contaminants.