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Knollwood, IL Tap Water Quality 2026

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

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

Main Utility: Lake Bluff PWSID: IL0970750 Updated: 2026 Q2
✅

No federal limits exceeded on record

Lead is 5.60 ppb, 37% of the action level and no violations are open. No PFAS was detected.

B

Knollwood earns a B for water quality

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

Lead: 5.60 ppb — 37% of the federal action level
PFAS tested, none detected
4 violations since 2015, 0 health-based
No violations currently open
Knollwood's lead level vs. all Illinois community water systems
0 ppb5 ppb10 ppb15 ppb
Lead level: 5.60 ppb — 37% of the federal action level
✓ Lower lead than 28% of Illinois utilities
Population Served
1773
~2083 connections
Water Source
Surface water
Purchased from another system — SDWIS source code SWP
Active Violations
0
4 since 2015, all resolved

Lead & Copper Testing

Lead (Pb)
90th percentile of tap samples collected across the distribution system
37% of EPA action level
5.60 ppb
Action level: 15 ppb
The 90th-percentile lead result is 5.60 ppb, 37% 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
Lead and Copper Rule MONITORING AND REPORTING — TT 2026 Unaddressed
Consumer Confidence Rule OTHER — — 2025 Unaddressed
Lead and Copper Rule MONITORING AND REPORTING — TT 2023 Resolved
Consumer Confidence Rule OTHER — — 2018 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

4 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 Lake Bluff
PWSID IL0970750
Water source Surface water — Purchased from another system — SDWIS source code SWP
Population served 1,773
Service connections 2,083
Systems serving this area 2
Regulator State primacy agency
Data through 2026 Q2 — EPA SDWIS

Frequently Asked Questions

Is Knollwood tap water safe to drink? ▼
No federal limit is exceeded on record. No violations are currently open. Lead is 5.60 ppb, 37% of the action level.
Does Knollwood water have PFAS? ▼
It was tested for the six regulated PFAS compounds and none were detected.
Who supplies water to Knollwood? ▼
Lake Bluff (PWSID IL0970750), one of 2 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 2024-07-16. Inspectors recorded 1 significant deficiency.

What Should Knollwood 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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