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Mount Prospect, IL Tap Water Quality 2026

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

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

Main Utility: Mount Prospect PWSID: IL0311980 Updated: 2026 Q2
✅

No federal limits exceeded on record

Lead is 4.27 ppb, 28% of the action level and no violations are open. No PFAS was detected.

A

Mount Prospect earns an A for water quality

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

Lead: 4.27 ppb — 28% of the federal action level
PFAS tested, none detected
10 violations since 2015, 0 health-based
No violations currently open
Mount Prospect's lead level vs. all Illinois community water systems
0 ppb5 ppb10 ppb15 ppb
Lead level: 4.27 ppb — 28% of the federal action level
✓ Lower lead than 36% of Illinois utilities
Population Served
40503
~11590 connections
Water Source
Surface water
Purchased from another system — SDWIS source code SWP
Active Violations
0
10 since 2015, all resolved

Lead & Copper Testing

Lead (Pb)
90th percentile of tap samples collected across the distribution system
28% of EPA action level
4.27 ppb
Action level: 15 ppb
The 90th-percentile lead result is 4.27 ppb, 28% 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
Consumer Confidence Rule OTHER — — 2025 Resolved
Consumer Confidence Rule OTHER — — 2025 Unaddressed
Revised Total Coliform Rule MONITORING FAILURE — — 2024 Resolved
Xylenes, Total MONITORING AND REPORTING — 10 mg/L 2024 Resolved
Toluene MONITORING AND REPORTING — 1 mg/L 2024 Resolved
Ethylbenzene MONITORING AND REPORTING — 0.7 mg/L 2024 Resolved
Benzene MONITORING AND REPORTING — 0.005 mg/L 2024 Resolved
Lead and Copper Rule MONITORING AND REPORTING — TT 2020 Resolved
Consumer Confidence Rule OTHER — — 2017 Resolved
Consumer Confidence Rule OTHER — — 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

10 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 Mount Prospect
PWSID IL0311980
Water source Surface water — Purchased from another system — SDWIS source code SWP
Population served 40,503
Service connections 11,590
Systems serving this area 9
Regulator State primacy agency
Data through 2026 Q2 — EPA SDWIS

Frequently Asked Questions

Is Mount Prospect tap water safe to drink? ▼
No federal limit is exceeded on record. No violations are currently open. Lead is 4.27 ppb, 28% of the action level.
Does Mount Prospect water have PFAS? ▼
It was tested for the six regulated PFAS compounds and none were detected.
Who supplies water to Mount Prospect? ▼
Mount Prospect (PWSID IL0311980), one of 9 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 2025-08-26. Inspectors recorded 1 significant deficiency.

What Should Mount Prospect 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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