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Oak Brook, IL Tap Water Quality 2026

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

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

Main Utility: Oak Brook PWSID: IL0430700 Updated: 2026 Q2
✅

No federal limits exceeded on record

Lead is 0.83 ppb, 6% of the action level and no violations are open. No PFAS was detected.

A

Oak Brook earns an A for water quality

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

Lead: 0.83 ppb — 6% of the federal action level
PFAS tested, none detected
3 violations since 2015, 0 health-based
No violations currently open
Oak Brook's lead level vs. all Illinois community water systems
0 ppb5 ppb10 ppb15 ppb
Lead level: 0.83 ppb — 6% of the federal action level
✓ Lower lead than 94% of Illinois utilities
Population Served
7756
~3295 connections
Water Source
Surface water
Purchased from another system — SDWIS source code SWP
Active Violations
0
3 since 2015, all resolved

Lead & Copper Testing

Lead (Pb)
90th percentile of tap samples collected across the distribution system
6% of EPA action level
0.83 ppb
Action level: 15 ppb
The 90th-percentile lead result is 0.83 ppb, 6% 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
Total Haloacetic Acids (HAA5) MONITORING AND REPORTING — 0.060 mg/L 2024 Resolved
Consumer Confidence Rule OTHER — — 2024 Resolved
Lead and Copper Rule MONITORING AND REPORTING — TT 2023 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 Oak Brook
PWSID IL0430700
Water source Surface water — Purchased from another system — SDWIS source code SWP
Population served 7,756
Service connections 3,295
Systems serving this area 7
Regulator State primacy agency
Data through 2026 Q2 — EPA SDWIS

Frequently Asked Questions

Is Oak Brook tap water safe to drink? ▼
No federal limit is exceeded on record. No violations are currently open. Lead is 0.83 ppb, 6% of the action level.
Does Oak Brook water have PFAS? ▼
It was tested for the six regulated PFAS compounds and none were detected.
Who supplies water to Oak Brook? ▼
Oak Brook (PWSID IL0430700), one of 7 systems serving this area. Surface water. Purchased from another system — SDWIS source code SWP
When was this system last inspected? ▼
It was last inspected on 2024-06-25. Inspectors recorded 1 significant deficiency.

What Should Oak Brook 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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