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City water profile

Ann Arbor water quality

Compare local ZIP estimates, evidence quality, associated public systems, and compliance history for Ann Arbor, Michigan.

Median indexed hardness

240PPM

5 indexed ZIPs

Range 240–240 PPM

State comparison
43 PPM below
State hardness rank
#239 of 374
Matched utilities
7
Active health records
0

City summary

What the indexed records say

Ann Arbor has 5 published ZIP profiles across Washtenaw County. The indexed median is 240 PPM, compared with 283 PPM across Michigan.

Among the 374 Michigancities with an indexed median, Ann Arbor ranks #239from highest to lowest. Across all 512 state ZIP profiles, available estimates run from 41.3to 459.5 PPM.

The 240–240 PPM range shows how much the available ZIP estimates vary within the city label. At least one estimate is marked low confidence, so observation distance and date deserve extra attention.

Hardness distribution

How local ZIP estimates compare

Soft0 ZIPs
Moderately hard0 ZIPs
Hard0 ZIPs
Very hard5 ZIPs

5 of 5 ZIP profiles have a hardness estimate. Bars count ZIP profiles, not households or laboratory samples.

Evidence quality

Distance, dates, and confidence

Median nearest distance
42.8 miles
Profiles with evidence
5/5

Confidence labels

High: 0Moderate: 0Low: 5

Observation window: Jan 7, 2016 to Jun 9, 2026.

ZIP directory

Water reports in Ann Arbor

Open a ZIP for site-level provenance and measurements.

ZIP code

48103

Very Hard

240 PPM

Nearest site
48.4 mi
Confidence
Low

View full ZIP evidence →

ZIP code

48104

Very Hard

240 PPM

Nearest site
42.8 mi
Confidence
Low

View full ZIP evidence →

ZIP code

48105

Very Hard

240 PPM

Nearest site
39.5 mi
Confidence
Low

View full ZIP evidence →

ZIP code

48108

Very Hard

240 PPM

Nearest site
45.1 mi
Confidence
Low

View full ZIP evidence →

ZIP code

48109

Very Hard

240 PPM

Nearest site
41.3 mi
Confidence
Low

View full ZIP evidence →

Public water systems

Utilities associated with this city

Ann Arbor

PWSID MI0000220

Surface water
System population served
123,851
Last reported
Jun 23, 2026

The system names this served city; Census place overlap links the city to this ZCTA.

Pittsfield Township

PWSID MI0005360

Surface water
System population served
24,500
Last reported
Jun 23, 2026

The system names this served city; Census place overlap links the city to this ZCTA.

Scio Township

PWSID MI0005977

Surface water
System population served
8,500
Last reported
Jun 23, 2026

The system names this served city; Census place overlap links the city to this ZCTA.

Loch Alpine Sanitary Authority

PWSID MI0003940

Groundwater
System population served
1,506
Last reported
Jun 23, 2026

The system names this served city; Census place overlap links the city to this ZCTA.

Ann Arbor Township

PWSID MI0000221

Surface water
System population served
1,338
Last reported
Jun 23, 2026

The system names this served city; Census place overlap links the city to this ZCTA.

Barton Hills

PWSID MI0000430

Groundwater
System population served
450
Last reported
Jun 23, 2026

The system names this served city; Census place overlap links the city to this ZCTA.

Sisters Of Mary, Mother Of Eucharist

PWSID MI0006074

Groundwater
System population served
100
Last reported
Jun 23, 2026

The system names this served city; Census place overlap links the city to this ZCTA.

Compliance history

What EPA records show

No active health-based violation appears among the associated systems in the represented EPA reporting quarter. This does not mean every contaminant was tested at every tap.

RecordSystemPeriodStatus
LEAD AND COPPER RULE REVISIONSMI0003940Jul 2, 2025Unaddressed
LEAD AND COPPER RULE REVISIONSMI0000430Jul 2, 2025Resolved
Consumer Confidence RuleMI0005360Jul 1, 2025Resolved
Revised Total Coliform RuleMI0005977Nov 11, 2024Resolved
Consumer Confidence RuleMI0000430Jul 1, 2024Resolved
Revised Total Coliform RuleMI0005977Nov 11, 2023Resolved
TTHMMI0005360Oct 1, 2023Resolved
Total Haloacetic Acids (HAA5)MI0005360Oct 1, 2023Resolved
Lead and Copper RuleMI0003940Oct 1, 2023Resolved
Lead and Copper RuleMI0005977Oct 11, 2022Resolved

Practical next steps

Move from index to evidence

  1. 1. Open your ZIP. Check distance, dates, confidence, and the associated utility.
  2. 2. Read the current CCR. Confirm source water, detections, limits, ranges, and notices.
  3. 3. Test the tap when needed. Confirm health concerns or treatment sizing with the right method.

Questions people ask

About water in Ann Arbor

Is the water hard?

The indexed city median is 240 PPM. Open the ZIP report to verify the distance and confidence behind that estimate.

Is the tap water safe?

Compliance history is utility-wide and cannot guarantee conditions at every tap. Check current notices and test when address-specific evidence is needed.

Do I need treatment?

Choose treatment only after confirming the problem at the property. A softener targets hardness; contaminant treatment requires a matching, verified performance claim.