What's in ANN ARBOR's water?
ANN ARBOR has a health-based violation on record, but none in the last five years - an older issue, not necessarily a current one. Population served: 123,851, over 26,050 connections.
ANN ARBOR's record against the rest of the country
Out of 12,903 systems in this dataset, ANN ARBOR ranks 573th by violation burden (96th percentile) - 43 violations total, 30 health-baseds.
How ANN ARBOR compares within MI
Among the 390 MI systems in this dataset, the average is 1.3 health-based violations - ANN ARBOR's 30 is above that. The clean-record guide covers what a comparison like this can hide.
Most recent violation on record
The last violation EPA has on record for ANN ARBOR is from 2016-01-11 (health-based: 2008-01-01). Last reported to EPA: 06/23/2026.
What kind of problem, specifically
ANN ARBOR's flagged contaminants and rule violations, grouped by what they actually mean for a filter choice rather than left as EPA's raw code list:
- Microbial contamination / treatment technique - flagged from: Interim Enhanced Surface Water Treatment Rule; Surface Water Treatment Rule
The most severe category on record is microbial contamination / treatment technique, which points toward a microbial-class filter if you want to address it directly.
What this data is and is not
This is what ANN ARBOR reported to its state primacy agency and EPA under the Safe Drinking Water Act - real regulatory record, not a lab test of your specific tap. This record - 30 health-based violations on file for ANN ARBOR - stops at the meter and cannot see household plumbing on the other side of it. The guide to what this data misses covers that gap.