A85/100
WINNETKA — Water Quality Report 2026
Serving 12,475 people · Illinois
Water Source
Surface Water
County
—
System ID
IL0313330
Violations
12
Contaminant Test Results
1 contaminant above EPA health goals
| Contaminant | Detected | Limit (MCL) | Status |
|---|---|---|---|
Lead (90th percentile) | 0.009 mg/L | 0.015 mg/L | Above Goal |
EPA Violation History
No violations in the past 5 years
Full EPA compliance since 2010.
Understanding violation severity
Tier 1Urgent health risk. Utility must notify all customers within 24 hours.Tier 2Important health or treatment issue. Customers notified within 30 days.Tier 3Administrative or monitoring issue. Reported in the annual water quality report.
Source: EPA Safe Drinking Water Information System (SDWIS) · Updated quarterly
Frequently Asked Questions About WINNETKA
Is WINNETKA water safe to drink?
WINNETKA water receives a grade of A (85/100), which is considered excellent. Out of 69 contaminants tested, none exceed EPA legal limits. 1 contaminant(s) exceed non-enforceable health goals. The water meets federal safety standards.
What contaminants has WINNETKA detected?
69 contaminants were tested in WINNETKA's water. Notable contaminants include Lead (90th percentile). No contaminants exceed EPA legal limits. 1 exceed EPA health goals (MCLGs).
Does WINNETKA have any EPA violations?
Yes, WINNETKA has 12 EPA violation(s) on record, with the most recent in 2010. Violation types include Other, MR.
How many people does WINNETKA serve?
WINNETKA serves approximately 12,475 people, Illinois. The system provides water to 1 community: Winnetka.
What type of water does WINNETKA provide?
WINNETKA sources its water from surface water. Surface water comes from rivers, lakes, or reservoirs and typically requires more extensive treatment. The utility's system ID is IL0313330.
How does WINNETKA compare to other utilities in Illinois?
WINNETKA scores 85/100 with a grade of A (excellent). This places it among the higher-performing utilities in the state. Visit our Illinois state page for a full comparison of water systems.