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Oswego, IL Tap Water Quality 2026

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

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

Main Utility: Oswego PWSID: IL0930150 Updated: 2026 Q2
✅

No federal limits exceeded on record

Lead was not detected and no violations are open. No PFAS was detected.

B

Oswego earns a B for water quality

Graded on violations, lead, and PFAS, with state inspection findings.

Lead: not detected
PFAS tested, none detected
6 violations since 2015, 1 health-based
No violations currently open
Oswego's lead level vs. all Illinois community water systems
0 ppb5 ppb10 ppb15 ppb
Lead level: Not detected — 0% of the federal action level
✓ Lower lead than % of Illinois utilities
Population Served
31370
~12887 connections
Water Source
Groundwater
Drawn from wells — SDWIS source code GW
Active Violations
0
6 since 2015, all resolved

Lead & Copper Testing

Lead (Pb)
90th percentile of tap samples collected across the distribution system
0% of EPA action level
Not detected
Action level: 15 ppb
Lead was not detected at the 90th percentile — the result fell below the laboratory detection limit. That is not the same as an absence of lead in every tap, and older homes with lead service lines can still show higher readings.

Contaminant Violations (2015–Present)

ContaminantTypeMeasuredLimitPeriodStatus
Chlorine MONITORING AND REPORTING — 4.0 mg/L 2024 Resolved
Consumer Confidence Rule OTHER — — 2022 Resolved
Consumer Confidence Rule OTHER — — 2017 Resolved
Public Notice OTHER — — 2017 Resolved
Combined Radium (-226 and -228) MCL EXCEEDANCE 6 PCI/L 5 pCi/L 2017 Resolved
Combined Radium (-226 and -228) MONITORING AND REPORTING — 5 pCi/L 2016 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

6 violations are on record since 2015, of which 1 were health-based. All have been resolved and none remain open.

About the Main Water System

Utility Oswego
PWSID IL0930150
Water source Groundwater — Drawn from wells — SDWIS source code GW
Population served 31,370
Service connections 12,887
Systems serving this area 3
Regulator State primacy agency
Data through 2026 Q2 — EPA SDWIS

Frequently Asked Questions

Is Oswego tap water safe to drink? ▼
No federal limit is exceeded on record. No violations are currently open.
Does Oswego water have PFAS? ▼
It was tested for the six regulated PFAS compounds and none were detected.
Who supplies water to Oswego? ▼
Oswego (PWSID IL0930150), one of 3 systems serving this area. Groundwater. Drawn from wells — SDWIS source code GW
When was this system last inspected? ▼
It was last inspected on 2025-10-22. Inspectors recorded 1 significant deficiency.

What Should Oswego 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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