Onawa Municipal Water Plant
EPA ID: IA6739095 · 2,906 people served · 1 ZIP code
For the full five-year period covered by EPA monitoring, Onawa Municipal Water Plant has supplied tap water to 2,906 residents with no violations of any type on record.
Data: EPA SDWIS Last verified: 2026-04-02
Service Area Map
Coverage area for Onawa Municipal Water Plant Source: EPA SDWIS service area boundaries.
Service area boundary — Grade B
Service Area Demographics
The Onawa Municipal Water Plant serves a community with a median household income of $60,642 and an estimated 3,388 residents across its service area. Approximately 81% of housing stock was built before 1986, which increases the likelihood of lead service lines and older plumbing.
💧 Where Does Your Water Come From?
Onawa Municipal Water Plant'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 Monona County, Iowa rely on private wells rather than public water systems. Private well owners are responsible for their own water testing and treatment.
Infrastructure Risk
Comparable Water Systems
Similar-sized systems in Iowa
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
Onawa Municipal Water Plant (EPA ID: IA6739095) is a community water system in Iowa that serves approximately 2,906 people from groundwater sources.
This system serves ZIP code 51040 in Onawa.
Average Home Safety Score: B (70/100)
Based on water quality violations, lead levels, and radon risk across all ZIP codes served by this system.
Violation History
Lead & Copper
EPA Lead and Copper Rule sampling data for ZIP codes served by this system:
| ZIP Code | Lead Level | Exceeds Limit | Sample Date |
|---|---|---|---|
| 51040 | 0.002 mg/L | No | N/A |
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 IA or modeled from parcel and building-footprint data.
- 51040 — Onawa
Data Sources
This report uses public data from the EPA Safe Drinking Water Information System (SDWIS). View the full compliance record for Onawa Municipal Water Plant (IA6739095) on EPA.gov.
Frequently Asked Questions
Is Onawa Municipal Water Plant water safe to drink?
Based on EPA records, Onawa Municipal Water Plant has no recorded violations in the past 5 years — a positive indicator of water quality management.
How many people does Onawa Municipal Water Plant serve?
Onawa Municipal Water Plant serves approximately 2,906 people across 1 ZIP code in Iowa.
Where does Onawa Municipal Water Plant get its water?
The primary water source is groundwater.
Federal UCMR5 PFAS Monitoring: Tested Clean
This water system was tested under the federal EPA Unregulated Contaminant Monitoring Rule (UCMR5). No PFAS compounds were detected.
Current MCL reflects the lowest state-enforceable limit (NYS 10 ppt for PFOA/PFOS, effective August 2020). The federal final MCL of 4 ppt for PFOA/PFOS (EPA April 2024 rule) is not enforceable until April 2029. Detections above 4 ppt but below 10 ppt are below current MCL but above the future federal limit.
Source: U.S. EPA UCMR5 (Unregulated Contaminant Monitoring Rule, 5th cycle) — per-system federal sampling, 2023–2025. EPA UCMR5 monitoring program →
Lead Service Line Inventory
Service line breakdown reported under the federal Lead and Copper Rule Improvements (LCRI) inventory requirement:
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.