A92/100
THORNTON — Water Quality Report 2026
Serving 2,333 people · Illinois
Water Source
Purchased Surface Water
County
—
System ID
IL0313090
Violations
5
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
3
Violations (last 5yr)
1
Unresolved
0
Health-Related
TIER 3Unresolved
Surface water treatment technique failure
TIER 3Resolved
Surface water treatment technique failure
When: July 1, 2022 – June 19, 2023Enforcement: Resolving — corrective action underway
TIER 3Resolved
Surface water treatment technique failure
When: July 1, 2021 – July 19, 2021Enforcement: Resolving — corrective action underway
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 THORNTON
Is THORNTON water safe to drink?
THORNTON water receives a grade of A (92/100), which is considered excellent. Out of 1 contaminants tested, none exceed EPA legal limits. 1 contaminant(s) exceed non-enforceable health goals. The water meets federal safety standards.
What contaminants has THORNTON detected?
1 contaminants were tested in THORNTON's water. Notable contaminants include Lead (90th percentile). No contaminants exceed EPA legal limits. 1 exceed EPA health goals (MCLGs).
Does THORNTON have any EPA violations?
Yes, THORNTON has 5 EPA violation(s) on record, with the most recent in 2025. Violation types include Other, MR.
How many people does THORNTON serve?
THORNTON serves approximately 2,333 people, Illinois. The system provides water to 1 community: Thornton.
What type of water does THORNTON provide?
THORNTON 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 IL0313090.
How does THORNTON compare to other utilities in Illinois?
THORNTON scores 92/100 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.