Water Quality in Ann Arbor, MI: 56 Violations — Grade C
Grade C · Score 62/100 · 5 water systems · Updated 2026-05-03
Ann Arbor's water has moderate compliance issues. Residents in affected areas should consider filtration.
Data: EPA Safe Drinking Water Information System (SDWIS) Last verified: 2026-05-03
The compliance record maintained by the EPA for Ann Arbor, MI documents 56 water violations — each tied to a specific public water system and assigned a violation category in the federal Safe Drinking Water dataset.
Water Quality Map: Ann Arbor, MI
Each dot represents a ZIP code. Color indicates water quality grade. Tap a dot for details.
Water Quality by ZIP Code in Ann Arbor
Water quality varies across Ann Arbor's 8 ZIP codes. Check your specific ZIP for detailed contaminant data.
| ZIP Code | Grade | Score | Violations | Health | |
|---|---|---|---|---|---|
| 48103 | C | 60 | 7 | 0 | View report → |
| 48104 | C | 60 | 7 | 0 | View report → |
| 48106 | C | 61 | 7 | 0 | View report → |
| 48107 | C | 61 | 7 | 0 | View report → |
| 48109 | C | 61 | 7 | 0 | View report → |
| 48113 | C | 61 | 7 | 0 | View report → |
| 48105 | C | 65 | 7 | 0 | View report → |
| 48108 | C | 65 | 7 | 0 | View report → |
Water Quality Overview
Ann Arbor, Michigan receives a water quality grade of C with an overall score of 62 out of 100, based on EPA compliance data from the Safe Drinking Water Information System (SDWIS).
The 5 water systems serving Ann Arbor have accumulated 56 EPA violations (all monitoring/reporting type). These violations are tracked across 8 ZIP codes serving approximately 277,712 people.
What Grade C Means
A grade of C indicates moderate compliance issues. Ann Arbor's water systems have some violations that warrant attention. While the water may still be safe for most people, residents in affected ZIP codes should consider additional testing or filtration.
Lead Levels
The average 90th percentile lead level across Ann Arbor water systems is 0.0023 mg/L — within EPA limits. No ZIP codes exceed the EPA lead action level.
With 62% of homes built before 1986, Ann Arbor has a higher-than-average risk of lead from older plumbing. Lead solder was banned in 1986, and homes built before this date may have lead in pipes, solder joints, or fixtures.
Radon Risk
Ann Arbor is in EPA Radon Zone 1 (High risk). The EPA recommends all homes in Zone 1 areas be tested for radon. Radon is the second leading cause of lung cancer after smoking.
Water Systems Serving Ann Arbor
Ann Arbor is served by 5 community water systems regulated under the Safe Drinking Water Act. These systems collectively serve approximately 277,712 people across 8 ZIP codes.
Each water system is identified by a Public Water System ID (PWSID) and is required to:
- Test for over 90 regulated contaminants on a regular schedule
- Report results to the EPA and state regulators
- Issue an annual Consumer Confidence Report (CCR) to all customers
- Take corrective action when violations occur
The EPA has taken 80 enforcement actions against water systems serving Ann Arbor. Enforcement actions range from informal compliance assistance to formal orders and penalties.
How to Check Your Water in Ann Arbor
Enter your ZIP code on ZipCheckup to see your specific water system data, including contaminant levels, violation history, and safety scores
Request your CCR — your water utility must provide an annual Consumer Confidence Report with detailed test results for all monitored contaminants
Get a home test — certified kits cost $20–$50 and test for lead, bacteria, and common contaminants. Professional lab tests ($150–$400) cover a broader panel
Consider filtration — NSF-certified filters can remove specific contaminants. Reverse osmosis removes the broadest range; activated carbon is effective for chlorine and many organics
Check for advisories — monitor your local utility website and local news for boil water advisories or system alerts
Contaminants Detected in Ann Arbor Water Systems
The following contaminants have been detected or caused violations across Ann Arbor's water systems:
| Contaminant | Category | MCL | Violations | ZIPs Affected | Health-Based |
|---|---|---|---|---|---|
| Total Trihalomethanes (TTHM) | Disinfection Byproducts | 0.08 mg/L | 16 | 8 | No |
| Surface Water Treatment Rule | Treatment Technique | N/A | 16 | 8 | No |
| Stage 1 DBP Rule | Treatment Technique | N/A | 8 | 8 | No |
MCL = Maximum Contaminant Level (EPA enforceable standard). Health-based violations indicate levels that may pose direct health risks.
EPA Enforcement History
The EPA and state regulators have taken 10 enforcement actions against water systems serving Ann Arbor. Recent actions:
| Date | Action Type |
|---|---|
| 2025-05-30 | State Informal Action |
| 2024-12-05 | State Informal Action |
| 2024-12-05 | State Informal Enforcement |
| 2024-12-05 | State Filed Motion |
| 2024-12-02 | State Order Extension |
| 2024-07-10 | State Informal Action |
| 2024-06-26 | State Informal Action |
| 2024-05-06 | State Order Extension |
| 2024-04-02 | State Informal Action |
| 2024-02-02 | State Informal Action |
Enforcement actions range from informal compliance assistance to formal orders and penalties. The most recent action was on 2025-05-30.
Ann Arbor vs. Nearby Michigan Cities
How Ann Arbor's water quality compares to similar cities in Michigan:
| City | Grade | Violations | Systems | Population |
|---|---|---|---|---|
| Ann Arbor | C | 56 | 5 | 277,712 |
| Grand Rapids | B | 0 | 5 | 315,695 |
| Lansing | B | 72 | 5 | 194,168 |
| Kalamazoo | B | 120 | 5 | 193,444 |
Recommended Water Filters for Ann Arbor
Based on contaminants detected in Ann Arbor's water supply, these filter types are recommended:
Reverse Osmosis (under-sink)
- Removes: Copper
- Effectiveness: 95-99%
- Cost range: $150–$500
- Certification: NSF/ANSI 58
- Recommended products:
Water Quality by ZIP Code in Ann Arbor
Water quality varies across Ann Arbor's ZIP codes. The table below shows the worst-scoring and best-scoring areas:
| ZIP Code | Score | Grade | Violations | Health-Based |
|---|---|---|---|---|
| 48103 | 60 | C | 7 | 0 |
| 48104 | 60 | C | 7 | 0 |
| 48106 | 61 | C | 7 | 0 |
| 48107 | 61 | C | 7 | 0 |
| 48109 | 61 | C | 7 | 0 |
| 48113 | 61 | C | 7 | 0 |
| 48105 | 65 | C | 7 | 0 |
| 48108 | 65 | C | 7 | 0 |
Common Questions About Ann Arbor Water
These are the most common questions residents search for about water quality in Ann Arbor, Michigan:
Is Ann Arbor water hard or soft? Water hardness varies by source. Ann Arbor's 5 water systems use multiple sources. Check your ZIP code report for specific hardness data.
Can I drink Ann Arbor tap water? Ann Arbor's water receives a grade of C (62/100). No health-based violations have been recorded, but home testing is always recommended.
What is the best water filter for Ann Arbor? Based on detected contaminants, a reverse osmosis (under-sink) filter is most recommended. See our Water Filter Matcher for personalized recommendations.
Ann Arbor vs. Michigan Average
Understanding how Ann Arbor compares to the broader Michigan average helps contextualize your local water quality. Factors like water source, treatment methods, and infrastructure age all contribute to differences between cities in the same state.
To see how individual neighborhoods compare, check the ZIP code reports below — water quality can vary significantly even within Ann Arbor.
ZIP Codes in Ann Arbor
Ann Arbor spans 8 ZIP codes. The ZIP with the lowest water quality score is 48103. Each ZIP code has its own water quality profile based on the specific water system serving that area. Check each ZIP code for detailed contaminant data, violation history, and system information.
Data Sources
- Water quality: EPA Safe Drinking Water Information System (SDWIS)
- Lead/copper: EPA Lead and Copper Rule sampling data
- Radon: EPA Map of Radon Zones
- Enforcement: EPA ECHO database
- Filter recommendations: NSF/ANSI certified products
Updated daily.