F0/100
ANN ARBOR — Water Quality Report 2026
Serving 241,868 people · Michigan
Water Source
Surface Water
County
—
System ID
MI0000220
Violations
42
Contaminant Test Results
2 contaminants above EPA health goals
| Contaminant | Detected | Limit (MCL) | Status |
|---|---|---|---|
chlorate | 400.00 µg/L | — | Above Goal |
Lead (90th percentile) | 0.002 mg/L | 0.015 mg/L | Above Goal |
EPA Violation History
No violations in the past 5 years
Full EPA compliance since 2016.
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 ANN ARBOR
Is ANN ARBOR water safe to drink?
ANN ARBOR water receives a grade of F (0/100), which is considered failing. 0 contaminant(s) exceed EPA legal limits and 42 violation(s) are on record. Customers may want to consider using a water filter.
What contaminants has ANN ARBOR detected?
76 contaminants were tested in ANN ARBOR's water. Notable contaminants include Lead (90th percentile), chlorate. No contaminants exceed EPA legal limits. 2 exceed EPA health goals (MCLGs).
Does ANN ARBOR have any EPA violations?
Yes, ANN ARBOR has 42 EPA violation(s) on record, with the most recent in 2016. Violation types include MR, TT. 30 are health-based violations.
How many people does ANN ARBOR serve?
ANN ARBOR serves approximately 241,868 people, Michigan. The system provides water to 1 community: Ann Arbor.
What type of water does ANN ARBOR provide?
ANN ARBOR 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 MI0000220.
How does ANN ARBOR compare to other utilities in Michigan?
ANN ARBOR scores 0/100 with a grade of F (failing). This score suggests significant water quality concerns relative to other utilities. Visit our Michigan state page for a full comparison of water systems.