Washtenaw County, Michigan
19 ZIP codes · Avg score 64/100 · Grade C · Updated
ZipCheckup grade for Washtenaw County: C.
A mixed picture - some signals here are worth your attention.
Current EPA records place Washtenaw County in the middle tier for drinking water safety, with 19 ZIP codes showing a range of outcomes.
How Washtenaw County Compares
How Washtenaw County Compares
Washtenaw County scores 21 points below the Michigan state average (85/100) and 9 points below the national average (73/100).
Data: ZipCheckup Home Safety Score model 4.0.0; EPA SDWIS, UCMR 5, EPA radon zones, EPA AirData Last verified:
ZIP Code Risk Map
Water Quality Map: Washtenaw County, Michigan
Each dot represents a ZIP code. Color indicates water quality grade. Tap a dot for details.
Key Risk Factors
Health risk index: 10.4 (asthma 10.6%, diabetes 8.7%)
Estimated additional annual cost per homeowner: $1,375, driven primarily by flood
58.9% of homes built before 1978 (lead paint era)
Violation History (2022–2024)
→ Stable trendEPA violation counts by year across Washtenaw County water systems. Health-based shown in red, total in blue.
Peak year: 2023 with 7 violations. Past 5 years: 12 total (12 health-based).
Source: EPA SDWIS historical violations. Data may lag 6–12 months for the most recent year.
County Health Indicators vs National Average
Black markers indicate national averages. Source: CDC PLACES, Census ACS.
Infrastructure Overview
Modeled area-level indicator, not a failure probability. Sources: Census ACS housing age, EPA DWINS infrastructure needs, EPA SDWIS violations, and EPA lead indicators.
Compound Risk Breakdown
Estimated additional annual cost per homeowner: $1,375
Bar widths proportional to share of total annual risk cost. Source: compound risk model (FEMA, EPA, USGS).
Housing Age Distribution
151,771 housing units in Washtenaw County
Source: U.S. Census Bureau ACS B25034 (Year Structure Built).
Water Safety Affordability
How much it costs to fix water issues relative to home values in Washtenaw County
Remediation costs are relatively manageable for most homeowners in Washtenaw County, representing a small fraction of property value.
Remediation includes water filtration, lead abatement, radon mitigation, and flood protection where applicable. Source: Census ACS, EPA SDWIS.
Health Outcomes vs National Average
CDC PLACES data for Washtenaw County residents
Black markers = national averages. Red = above national avg. Green = below. Source: CDC PLACES, Census ACS.
Water systems serving Washtenaw County
8 community water systems serving Washtenaw County.
- C
- C
- C
- C
- C
- C
Show all 8 water systems
- C
- C
21 total water systems serve Washtenaw County.
Systems with the most violations in Washtenaw County
5 water systems with recorded EPA violations.
- C
- C
All ZIP Codes in Washtenaw County
19 ZIP codes tracked in Washtenaw County.
| # | ZIP Code | City | Safety Score | Grade | Violations | Home Value |
|---|---|---|---|---|---|---|
| 1 | 48104 | Ann Arbor | 67 | C | 0 | $482K |
| 2 | 48109 | Ann Arbor | 67 | C | 0 | — |
| 3 | 48118 | Chelsea | 67 | C | 0 | $349K |
| 4 | 48191 | Willis | 66 | C | 2 | $276K |
| 5 | 48108 | Ann Arbor | 65 | C | 5 | $378K |
| 6 | 48176 | Saline | 65 | C | 5 | $385K |
| 7 | 48197 | Ypsilanti | 65 | C | 4 | $274K |
| 8 | 48130 | Dexter | 64 | C | 6 | $453K |
| 9 | 48103 | Ann Arbor | 62 | C | 11 | $455K |
| 10 | 48105 | Ann Arbor | 62 | C | 11 (1 health) | $486K |
| 11 | 48198 | Ypsilanti | 55 | C | 32 (2 health) | $178K |
| 12 | 48106 | Ann Arbor | — | — | — | |
| 13 | 48107 | Ann Arbor | — | — | — | |
| 14 | 48113 | Ann Arbor | — | — | — | |
| 15 | 48115 | Bridgewater | — | — | — | |
| 16 | 48158 | Manchester | — | — | 0 | $298K |
| 17 | 48175 | Salem | — | — | — | |
| 18 | 48189 | Whitmore Lake | — | — | 32 (4 health) | $286K |
| 19 | 48190 | Whittaker | — | — | $220K |
Recommended Buyer Guides for Washtenaw County
Methodologically, the recommendation order reflects severity in the federal record: contaminants flagged in EPA detection records for this county outrank generic water concerns, FEMA-confirmed hazard ratings shift emergency-related categories upward, and CDC lead-exposure markers govern when lead-test kits and certified filters appear at the top of the list.
- Best Water Filters for PFAS — PFAS detected in 1 ZIP code
- Best Lead Paint Test Kits — 58.9% of homes built before 1978
- Best Under-Sink Reverse Osmosis Systems — Multi-contaminant removal at the kitchen tap
- Best Radon Test Kits — EPA Radon Zone 1 (highest risk) dominant in county
- Best Sump Pumps — Flood is the top compound risk factor
Deep Dive Reports
Detailed analysis for Washtenaw County, Michigan
Overview
Washtenaw County in Michigan covers 19 tracked ZIP records with an average Home Safety Score of C (64/100) across 11 scored records.
9 of 13 ZIP codes with a reported violation count in the available EPA record have recorded EPA violations. 6 health-based violations appear in the available health breakdown.
← Back to Michigan Home Safety Profile
Data Sources
- Water quality: EPA Safe Drinking Water Information System (SDWIS)
- PFAS screening: EPA UCMR 5
- Radon zones: EPA Map of Radon Zones
- Air quality: EPA AirData annual AQI
- Home values: U.S. Census Bureau ACS (median estimates by ZCTA)
Reporting periods vary by source. Missing data is shown as unavailable, not as zero.