Drinking water quality · 2024
· Verified
· PWSID MI0000220
What's in Ann Arbor, MI tap water
Every one of the 15 core regulated contaminants reported for Ann Arbor, MI came in below its federal limit.
- !2 contaminants within 20% of a limit
- !15 of 27 core regulated contaminants reported — 12 never appear in this report
- ✓Nothing over a federal limit
- ✓No open federal violations
+How this score is calculated
Every system starts at 100. Points come off for measured levels, for the federal violation record, and for how much of the core regulated set the utility actually reported. All three inputs are the utility's own published numbers and EPA's own records.
- −0 contaminants at or above a federal limit
- −8 contaminants within 20% of a limit
- −0 open health-based violations
- −0 open monitoring / reporting violations
- −0 health-based violations resolved in the last 5 years
- −6 core regulated contaminants never reported (15/27)
A 90–100 · B 80–89 · C 70–79 · D 60–69 · F below 60. A system reporting under a third of the core set is capped at C however clean its numbers look — a short report is not a clean bill of health.
Full grading methodology, constant for constant →What to worry about
- Bromate86% of the federal limit0–8.6 ug/L · limit 10 ug/L
Classified as a probable human carcinogen; the EPA sets a strict maximum contaminant level.
higher than 90% of U.S. systems
- Chloramine85% of the federal limit0.9–3.4 mg/L · limit 4 mg/L
Holds disinfection further into the pipe network, but is regulated under the same residual-disinfectant cap as chlorine.
higher than 75% of U.S. systems
+39 contaminants were measured and came in below the limitShow all
| Contaminant | Measured | Federal limit |
|---|---|---|
| Combined Radium | 2 pCi/L | 5 pCi/L |
| Arsenic | 3.9 ug/L | 10 ug/L |
| Gross Alpha | 3.75 pCi/L | 15 pCi/L |
| Fluoride | 0.82 mg/L | 4 mg/L |
| HAA5 | 12 ug/L | 60 ug/L |
| Turbidity | 0.2 NTU | 1 NTU |
| Lead | 2 ug/L | 15 ug/L |
| TTHM | 2.6–9.2 ug/L | 80 ug/L |
| Nitrate | 1.1 mg/L | 10 mg/L |
| Copper | 100 ug/L | 1300 ug/L |
| Barium | 88 ug/L | 2000 ug/L |
| NDMA | 3.1 ug/L | — |
| Perchlorate | 0.26 ug/L | — |
| Ammonia | Not detected mg/L | — |
| Chloride | 127 mg/L | — |
| Nitrite | Not detected mg/L | 1 mg/L |
| Sulfate | 51 mg/L | — |
| Calcium | 31 mg/L | — |
| Iron | Not detected mg/L | — |
| Magnesium | 13 mg/L | — |
| Manganese | Not detected mg/L | — |
| Mercury | Not detected ug/L | 2 ug/L |
| Potassium | 3.3 mg/L | — |
| Sodium | 71 mg/L | — |
| Zinc | Not detected ug/L | — |
| Total Coliform | 1 % | — |
| Chromium | Not detected ug/L | 100 ug/L |
| Perfluorobutanesulfonic acid | Not detected ng/L | — |
| PFAS | Not detected ng/L | — |
| Alkalinity | 54 mg/L | — |
| Hardness | 126 mg/L | — |
| pH | 9.3 | — |
| Specific Conductance | 636 | — |
| Temperature | 15.3 | — |
| TOC | 49.3–71.43 % | — |
| Total Solids | 351 mg/L | — |
| PFBA | 6.1000000000000005 ng/L | — |
| PFPeA | 4.7 ng/L | — |
| PFHxA | 3.5 ng/L | — |
What this report doesn't tell you
12 of the 27 contaminants a community water system normally reports do not appear anywhere in Ann Arbor, MI's data. Absent is not the same as absent-from-the-water — it means nobody published a number.
+Full detail: PFAS testing, water source, historical monitoring, and the federal violation record
PFAS — EPA UCMR5 (2023–2025)
3 PFAS compounds detected in Ann Arbor, MI
The EPA finalized the first-ever federal drinking-water limits for six PFAS compounds in April 2024. These numbers come straight from EPA's UCMR5 lab dataset — every U.S. system serving more than 3,300 people tested every PFAS sample at an entry point to its distribution system. PFAS not listed below were either tested and not detected, or not yet sampled.
PFBA
● Detected (no federal limit)PFPeA
● Detected (no federal limit)PFHxA
● Detected (no federal limit)Where your water comes from · EPA SDWIS
Ann Arbor, MI's drinking water comes from ground water, drawn from 5 sources.
Source
- WELL · 2
- HURON RIVER AT BARTON POND
- WELL 74-1
- HURON RIVER BARTON POND
Treatment
- TREATMENT PLANT
Distribution
Compliance history
Federal Safe Drinking Water Act violation & enforcement records (EPA SDWIS). A violation is a regulatory determination by the state or EPA — separate from the measured levels above.
- Treatment technique violationHealth-based30 violations on record · most recent Jan 2008resolved
Source: EPA SDWIS / ECHO. View the full federal record on EPA ECHO ↗