Onslow Water Supply
EPA ID: IA5358096 · 201 people served · 2 ZIP codes
Within the five-year EPA monitoring span, Onslow Water Supply accumulated 1 violation — every finding has been resolved and the utility operates in full compliance today, supplying water to approximately 201 people without any active enforcement proceedings.
Data: EPA SDWIS Last verified: 2026-04-02
Service Area Map
Coverage area for Onslow Water Supply Source: EPA SDWIS service area boundaries.
Service area boundary — Grade C
Service Area Demographics
The Onslow Water Supply serves a community with a median household income of $72,443 and an estimated 1,383 residents across its service area. Approximately 84% of housing stock was built before 1986, which increases the likelihood of lead service lines and older plumbing.
💧 Where Does Your Water Come From?
Onslow Water Supply'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 Jones County, Iowa rely on private wells rather than public water systems. Private well owners are responsible for their own water testing and treatment.
Wastewater Proximity Note: This service area ranks in the 70th percentile nationally for proximity to wastewater discharge points.
Infrastructure Risk
Detected Contaminants
How Onslow Water Supply compares to EPA limits
What This Means For You
Lead at 1 mg/L (action level) exceeds the EPA maximum of 0.015 mg/L (action level). Brain damage in children, kidney & blood pressure in adults. Consider reverse osmosis filtration.
Lead was detected in this water system. reverse osmosis filtration can reduce exposure.
Find a certified water filter →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
Onslow Water Supply (EPA ID: IA5358096) is a community water system in Iowa that serves approximately 201 people from groundwater sources.
This system provides water to 2 ZIP codes across 2 communities.
Average Home Safety Score: C (66/100)
Based on water quality violations, lead levels, and radon risk across all ZIP codes served by this system.
Violation History
Contaminants Detected
The following contaminants have been flagged in EPA records for this water system:
| Contaminant | Category | Violations | Health-Based |
|---|---|---|---|
| Lead | Inorganic | 1 | No |
Lead & Copper
EPA Lead and Copper Rule sampling data for ZIP codes served by this system:
| ZIP Code | Lead Level | Exceeds Limit | Sample Date |
|---|---|---|---|
| 52321 | 0.0006 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
Data Sources
This report uses public data from the EPA Safe Drinking Water Information System (SDWIS). View the full compliance record for Onslow Water Supply (IA5358096) on EPA.gov.
Frequently Asked Questions
Is Onslow Water Supply water safe to drink?
Onslow Water Supply has only monitoring/reporting violations, which are procedural in nature. The system meets federal health-based standards.
How many people does Onslow Water Supply serve?
Onslow Water Supply serves approximately 201 people across 2 ZIP codes in Iowa.
Where does Onslow Water Supply 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
Onslow Water Supply (EPA ID: IA5358096) — request the latest Consumer Confidence Report or ask about specific contaminants.