Mason City
EPA ID: IL1250350 · 2,558 people served · 1 ZIP code
Per EPA records, Mason City: 1 unresolved violation, 2,558 people in service area.
Data: EPA SDWIS Last verified: 2026-04-02
Service Area Map
Coverage area for Mason City Source: EPA SDWIS service area boundaries.
Service area boundary — Grade C
Service Area Demographics
The Mason City serves a community with a median household income of $71,012 and an estimated 2,848 residents across its service area. Approximately 87% of housing stock was built before 1986, which increases the likelihood of lead service lines and older plumbing.
Environmental Justice Note: 67% of the population in this service area is classified as disadvantaged under EPA's EJScreen criteria. 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 pumped from underground aquifers. 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.
About 1% of homes in Mason County, Illinois rely on private wells rather than public water systems. Private well owners are responsible for their own water testing and treatment.
Infrastructure Risk
Detected Contaminants
How Mason City compares to EPA limits
What This Means For You
Stage 2 DBP Rule at 1 mg/L exceeds the EPA maximum of mg/L.
Comparable Water Systems
Similar-sized systems in Illinois
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
Mason City (EPA ID: IL1250350) is a community water system in Illinois that serves approximately 2,558 people from groundwater sources.
This system serves ZIP code 62664 in Mason City.
Average Home Safety Score: C (60/100)
Based on water quality violations, lead levels, and radon risk across all ZIP codes served by this system.
Violation History
Recent Violations
| Date | Contaminant | Type | Status |
|---|---|---|---|
| July 2, 2025 | Stage 2 DBP Rule | Monitoring | Unresolved |
Contaminants Detected
The following contaminants have been flagged in EPA records for this water system:
| Contaminant | Category | Violations | Health-Based |
|---|---|---|---|
| Stage 2 DBP Rule | Treatment Failure | 1 | No |
Lead & Copper
No Lead and Copper Rule sampling data available for this water system.
Radon Risk in Service Area
Dominant radon zone for ZIP codes served by this system: Zone 1 (High Risk)
The EPA recommends testing homes in Zone 1 and Zone 2 areas for radon.
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: Let cold water run for 2 minutes before drinking — this helps flush lead from your pipes.
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 the full compliance record for Mason City (IL1250350) on EPA.gov.
Frequently Asked Questions
Is Mason City water safe to drink?
Mason City has only monitoring/reporting violations, which are procedural in nature. The system meets federal health-based standards.
How many people does Mason City serve?
Mason City serves approximately 2,558 people across 1 ZIP code in Illinois.
Where does Mason City get its water?
The primary water source is groundwater.
Lead Service Line Inventory
Service line breakdown reported under the federal Lead and Copper Rule Improvements (LCRI) inventory requirement:
This system reports zero confirmed lead service lines in its inventory. Unknown-material counts may still warrant verification.
Federal LCRI rule (effective October 2024) requires every public water system to inventory its service lines and complete lead-line replacement within 10 years.
Source: EPA SDWIS Federal Service Line Inventory (Phase 2) · Submitted 2026
ZipCheckup is not affiliated with the utility or state agency. Inventory figures render verbatim from the public LCRI submission cited above; ZipCheckup does not perform inspections or replacements.
Frequently Asked Questions
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.