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Onslow, IA Tap Water Quality 2026

Water quality report for Onslow, IA — PFAS, lead and copper results, violation history and state inspection findings from EPA SDWIS.

A look at Onslow's drinking water using EPA enforcement records: violations, lead and copper results, PFAS sampling and state inspection findings.

Main Utility: Onslow Water Supply PWSID: IA5358096 Updated: 2026 Q2
✅

No federal limits exceeded on record

Lead is 0.60 ppb, 4% of the action level and no violations are open. PFAS has never been sampled at this system.

B

Onslow earns a B for water quality

Graded on violations and lead, with state inspection findings. PFAS not tested.

Lead: 0.60 ppb — 4% of the federal action level
PFAS never sampled at this system
3 violations since 2015, 0 health-based
No violations currently open
Onslow's lead level vs. all Iowa community water systems
0 ppb5 ppb10 ppb15 ppb
Lead level: 0.60 ppb — 4% of the federal action level
✓ Lower lead than 98% of Iowa utilities
Population Served
201
~110 connections
Water Source
Groundwater
Drawn from wells — SDWIS source code GW
Active Violations
0
3 since 2015, all resolved

Lead & Copper Testing

Lead (Pb)
90th percentile of tap samples collected across the distribution system
4% of EPA action level
0.60 ppb
Action level: 15 ppb
The 90th-percentile lead result is 0.60 ppb, 4% of the 15 ppb federal action level. The action level is a treatment trigger, not a legal maximum, and it is measured across sampled taps rather than at any single home.

Contaminant Violations (2015–Present)

ContaminantTypeMeasuredLimitPeriodStatus
Nitrate MONITORING AND REPORTING — 10 mg/L 2022 Resolved
Consumer Confidence Rule OTHER — — 2019 Resolved
Consumer Confidence Rule OTHER — — 2017 Resolved
Understanding violation types MCL violations mean a contaminant exceeded the federal maximum limit — the most serious type.
TT (Treatment Technique) violations mean required treatment procedures weren't followed, but don't necessarily mean contamination occurred.

Violation History

3 violations are on record since 2015, of which 0 were health-based. All have been resolved and none remain open.

About the Main Water System

Utility Onslow Water Supply
PWSID IA5358096
Water source Groundwater — Drawn from wells — SDWIS source code GW
Population served 201
Service connections 110
Systems serving this area 1
Regulator State primacy agency
Data through 2026 Q2 — EPA SDWIS

Frequently Asked Questions

Is Onslow tap water safe to drink? ▼
No federal limit is exceeded on record. No violations are currently open. Lead is 0.60 ppb, 4% of the action level.
Does Onslow water have PFAS? ▼
This system has never been sampled for PFAS. EPA's national monitoring covered systems serving 3,300 people or more, so no results exist — which is not evidence that none is present.
Who supplies water to Onslow? ▼
Onslow Water Supply (PWSID IA5358096). Groundwater. Drawn from wells — SDWIS source code GW
When was this system last inspected? ▼
It was last inspected on 2026-01-28. No significant deficiencies were recorded.

What Should Onslow Residents Do?

1
Read your annual water report
Your supplier publishes a Consumer Confidence Report each July covering the prior year.
2
Check for a lead service line
Lead reaches tap water mainly through service lines and household plumbing. Suppliers now publish an inventory identifying lead lines.
3
Flush before drinking
If water has sat in pipes more than six hours, run the cold tap for two minutes before drinking or cooking.

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