A90/100
OAKBROOK TERRACE — Water Quality Report 2026
Serving 1,440 people · Illinois
Water Source
Purchased Surface Water
County
—
System ID
IL0430750
Violations
2
Contaminant Test Results
1 contaminant above EPA health goals
| Contaminant | Detected | Limit (MCL) | Status |
|---|---|---|---|
Copper (90th percentile) | 1.57 mg/L | 1.30 mg/L | Over Limit |
EPA Violation History
No violations in the past 5 years
Full EPA compliance since 2020.
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 OAKBROOK TERRACE
Is OAKBROOK TERRACE water safe to drink?
OAKBROOK TERRACE water receives a grade of A (90/100), which is considered excellent. Out of 2 contaminants tested, 1 exceed EPA legal limits. 1 contaminant(s) exceed non-enforceable health goals. The water meets federal safety standards.
What contaminants has OAKBROOK TERRACE detected?
2 contaminants were tested in OAKBROOK TERRACE's water. Notable contaminants include Copper (90th percentile). 1 exceed EPA legal limits (MCLs). 1 exceed EPA health goals (MCLGs).
Does OAKBROOK TERRACE have any EPA violations?
Yes, OAKBROOK TERRACE has 2 EPA violation(s) on record, with the most recent in 2020. Violation types include MR, Other.
How many people does OAKBROOK TERRACE serve?
OAKBROOK TERRACE serves approximately 1,440 people, Illinois. The system provides water to 1 community: Oak Brook Terr.
What type of water does OAKBROOK TERRACE provide?
OAKBROOK TERRACE sources its water from purchased surface water. Surface water comes from rivers, lakes, or reservoirs and typically requires more extensive treatment. The utility's system ID is IL0430750.
How does OAKBROOK TERRACE compare to other utilities in Illinois?
OAKBROOK TERRACE scores 90/100 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.