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Lisle, IL Tap Water Quality 2026

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

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

Main Utility: Naperville PWSID: IL0434670 Updated: 2026 Q2
✅

No federal limits exceeded on record

Lead is 7.10 ppb, 47% of the action level and no violations are open. No PFAS was detected.

B

Lisle earns a B for water quality

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

Lead: 7.10 ppb — 47% of the federal action level
PFAS tested, none detected
16 violations since 2015, 0 health-based
No violations currently open
Lisle's lead level vs. all Illinois community water systems
0 ppb5 ppb10 ppb15 ppb
Lead level: 7.10 ppb — 47% of the federal action level
✓ Lower lead than 19% of Illinois utilities
Population Served
12886
~45580 connections
Water Source
Surface water
Purchased from another system — SDWIS source code SWP
Active Violations
0
16 since 2015, all resolved

Lead & Copper Testing

Lead (Pb)
90th percentile of tap samples collected across the distribution system
47% of EPA action level
7.10 ppb
Action level: 15 ppb
The 90th-percentile lead result is 7.10 ppb, 47% 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 2023 Resolved
Heptachlor MONITORING AND REPORTING — 0.0004 mg/L 2023–2025 Archived
Simazine MONITORING AND REPORTING — 0.004 mg/L 2023–2025 Archived
Endrin MONITORING AND REPORTING — 0.002 mg/L 2023–2025 Archived
Hexachlorocyclopentadiene MONITORING AND REPORTING — 0.05 mg/L 2023–2025 Archived
Methoxychlor MONITORING AND REPORTING — 0.04 mg/L 2023–2025 Archived
Heptachlor epoxide MONITORING AND REPORTING — 0.0002 mg/L 2023–2025 Archived
Chlordane MONITORING AND REPORTING — 0.002 mg/L 2023–2025 Resolved
Atrazine MONITORING AND REPORTING — 0.003 mg/L 2023–2025 Archived
Toxaphene MONITORING AND REPORTING — 0.003 mg/L 2023–2025 Resolved
LASSO MONITORING AND REPORTING — — 2023–2025 Archived
HEXACHLOROBENZENE MONITORING AND REPORTING — 0.001 mg/L 2023–2025 Archived
Benzo(a)pyrene MONITORING AND REPORTING — 0.0002 mg/L 2023–2025 Resolved
Di(2-ethylhexyl) phthalate MONITORING AND REPORTING — 0.006 mg/L 2023–2025 Archived
BHC-GAMMA MONITORING AND REPORTING — 0.0002 mg/L 2023–2025 Archived
Di(2-ethylhexyl) adipate MONITORING AND REPORTING — 0.4 mg/L 2023–2025 Archived
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

16 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 Naperville
PWSID IL0434670
Water source Surface water — Purchased from another system — SDWIS source code SWP
Population served 12,886
Service connections 45,580
Systems serving this area 5
Regulator State primacy agency
Data through 2026 Q2 — EPA SDWIS

Frequently Asked Questions

Is Lisle tap water safe to drink? ▼
No federal limit is exceeded on record. No violations are currently open. Lead is 7.10 ppb, 47% of the action level.
Does Lisle water have PFAS? ▼
It was tested for the six regulated PFAS compounds and none were detected.
Who supplies water to Lisle? ▼
Naperville (PWSID IL0434670), one of 5 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 2025-09-22. Inspectors recorded 1 significant deficiency.

What Should Lisle Residents Do?

1
Consider a filter certified for lead
Look for NSF/ANSI 53 certification for lead reduction.
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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