Drinking water quality · 2024
· Verified
What's in Ann Arbor, MI tap water
40 contaminants were measured in the Ann Arbor, MI water system's 2024 annual report. Each is shown below against its federal limit.
- Reporting year
- 2024
- Contaminants measured
- 40
- Over federal limit
- 0
- Approaching the limit
- 2
- Service area
- MI
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)below national p90 (18 ng/L across detecting U.S. systems)
PFPeA
● Detected (no federal limit)below national p90 (15.95999999999999 ng/L across detecting U.S. systems)
PFHxA
● Detected (no federal limit)below national p90 (12.190000000000003 ng/L across detecting U.S. systems)
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
Disinfection byproducts
| Contaminant | Measured | Federal limit | Status |
|---|---|---|---|
| BromateA disinfection byproduct formed when bromide-containing water is treated with ozone. | 0–8.6 ug/LRangeSystem-wide | 10 ug/LMCL | Approaching the limit |
| HAA5Haloacetic acids — a group of five disinfection byproducts formed when disinfectants react with organic matter. | 12 ug/LReported levelSystem-wide | 60 ug/LMCL | Within the limit |
| TTHMTotal trihalomethanes — a group of four chemicals (including chloroform) formed when chlorine reacts with natural organic matter. | 2.6–9.2 ug/LRangeSystem-wide | 80 ug/LMCL | Within the limit |
| NDMA | 3.1 ug/LAverageSystem-wide | None set | Detected — no federal limit |
| PerchlorateA chemical used in rocket fuel and fireworks that can also form during disinfection. | 0.26 ug/LAverageSystem-wide | None set | Detected — no federal limit |
Disinfectants
| Contaminant | Measured | Federal limit | Status |
|---|---|---|---|
| ChloramineA longer-lasting disinfectant made by combining chlorine with ammonia. | 0.9–3.4 mg/LRangeSystem-wide | 4 mg/LMRDL | Approaching the limit |
Radionuclides
| Contaminant | Measured | Federal limit | Status |
|---|---|---|---|
| Combined RadiumCombined radium-226 and radium-228 — naturally occurring radioactive elements. | 2 pCi/LHighest single sampleSystem-wide | 5 pCi/LMCL | Within the limit |
| Gross AlphaGross alpha particle activity — a combined measure of alpha-emitting radioactive substances. | 3.75 pCi/LHighest single sampleSystem-wide | 15 pCi/LMCL | Within the limit |
Metals
| Contaminant | Measured | Federal limit | Status |
|---|---|---|---|
| ArsenicA naturally occurring element that also enters water from industry and agriculture. | 3.9 ug/LReported levelSystem-wide | 10 ug/LMCL | Within the limit |
| LeadA toxic metal that leaches into water from old service lines, solder, and plumbing fixtures. | 2 ug/L90th percentileAt the tap | 12 ug/LAction level | Within the limit |
| CopperA metal that enters water from corroding household plumbing. | 100 ug/L90th percentileAt the tap | 1300 ug/LAction level | Within the limit |
| BariumA metal from erosion of natural deposits and industrial discharge. | 88 ug/LReported levelSystem-wide | 2000 ug/LMCL | Within the limit |
| Chromium, TotalTotal chromium — the sum of all chromium forms, from natural deposits and industrial discharge. | Not detected ug/LAverageSystem-wide | None set | None detected |
| IronA naturally occurring metal common in groundwater. | Not detected mg/LAverageSystem-wide | None set | None detected |
| MercuryA toxic metal from erosion of natural deposits and industrial runoff. | Not detected ug/LAverageSystem-wide | None set | None detected |
| ZincA naturally occurring metal that can also enter water from corroding pipes. | Not detected ug/LAverageSystem-wide | None set | None detected |
| CalciumA naturally occurring mineral that contributes to water hardness. | 31 mg/LAverageSystem-wide | None set | Detected — no federal limit |
| MagnesiumA naturally occurring mineral that contributes to water hardness. | 13 mg/LAverageSystem-wide | None set | Detected — no federal limit |
| ManganeseA naturally occurring metal from soil and rock. | Not detected mg/LAverageSystem-wide | None set | Detected — no federal limit |
| PotassiumA naturally occurring mineral from rock and soil. | 3.3 mg/LAverageSystem-wide | None set | Detected — no federal limit |
| SodiumA naturally occurring salt component. | 71 mg/LAverageSystem-wide | None set | Detected — no federal limit |
Inorganic chemicals
| Contaminant | Measured | Federal limit | Status |
|---|---|---|---|
| FluorideA mineral often added to drinking water to help prevent tooth decay. | 0.82 mg/LReported levelSystem-wide | 4 mg/LMCL | Within the limit |
| NitrateA compound from fertilizer runoff, septic systems, and erosion of natural deposits. | 0–1.1 mg/LRangeSystem-wide | 10 mg/LMCL | Within the limit |
| Ammonia | Not detected mg/LAverageSystem-wide | None set | Detected — no federal limit |
| ChlorideA naturally occurring salt compound. | 127 mg/LAverageSystem-wide | None set | Detected — no federal limit |
| NitriteA compound from fertilizer runoff, sewage, and erosion of natural deposits. | Not detected mg/LAverageSystem-wide | None set | Detected — no federal limit |
| SulfateA naturally occurring mineral from rock and soil. | 51 mg/LAverageSystem-wide | None set | Detected — no federal limit |
PFAS ("forever chemicals")
| Contaminant | Measured | Federal limit | Status |
|---|---|---|---|
| PFAS | Not detected ng/LAverageSystem-wide | None set | None detected |
| Perfluorobutanesulfonic acidPerfluorobutanesulfonic acid, a shorter-chain PFAS 'forever chemical.' | Not detected ng/LAverageSystem-wide | None set | Detected — no federal limit |
Microbial
| Contaminant | Measured | Federal limit | Status |
|---|---|---|---|
| Total ColiformA group of bacteria used as an indicator of overall water-system sanitation. | 1Highest single sampleSystem-wide | None set | Detected — no federal limit |
Physical & aggregate
| Contaminant | Measured | Federal limit | Status |
|---|---|---|---|
| AlkalinityA measure of the water's capacity to neutralize acids. | 54 mg/LAverageSystem-wide | None set | Detected — no federal limit |
| HardnessA measure of dissolved calcium and magnesium minerals. | 126 mg/LAverageSystem-wide | None set | Detected — no federal limit |
| pHA measure of how acidic or basic the water is. | 9.3AverageSystem-wide | None set | Detected — no federal limit |
| Specific ConductanceA measure of how well water conducts electricity, which tracks dissolved mineral content. | 636AverageSystem-wide | None set | Detected — no federal limit |
| TemperatureThe measured temperature of the water sample. | 15.3AverageSystem-wide | None set | Detected — no federal limit |
| TOCTotal organic carbon — a measure of organic material dissolved in the water. | 49.3–71.43RangeSystem-wide | None set | Detected — no federal limit |
| Total Solids | 351 mg/LAverageSystem-wide | None set | Detected — no federal limit |
| TurbidityA measure of cloudiness from suspended particles in the water. | 0.3 NTURangeSystem-wide | None set | Detected — no federal limit |
People also ask about Ann Arbor, MI's water
+Is Ann Arbor, MI tap water safe to drink in 2024?
Every one of the 40 contaminants measured in Ann Arbor, MI's 2024 Consumer Confidence Report is below its federal limit. "Safe" under the EPA's drinking-water standards is health-based, not aesthetic — but by those standards, no measured contaminant in this report exceeds its enforceable threshold. Individual health concerns (e.g. immunocompromised, infant, pregnancy) may warrant additional filtering regardless of compliance.
+What contaminants are in Ann Arbor, MI tap water?
40 contaminants were measured in Ann Arbor, MI's 2024 Consumer Confidence Report, spanning metals, physical & aggregate, and inorganic chemicals. 12 have an enforceable federal limit; the rest are detected but unregulated. Every measured value, in the utility's own units, is on this page.
+Are any contaminants in Ann Arbor, MI tap water approaching the federal limit?
2 contaminants are between 80% and 100% of the federal limit in this report: Bromate and Chloramine. Approaching means measured but not in violation — a margin that can close quickly if conditions change.
+Where does the data on this page come from?
Every value is transcribed from Ann Arbor, MI's 2024 Consumer Confidence Report — the annual drinking-water report every U.S. public water utility is required by federal law to publish. The original source document is archived and viewable on this site. A water-quality report covers an entire service area, not a single address.
+How often is Ann Arbor, MI's water quality data updated?
Each U.S. public water utility publishes one Consumer Confidence Report per year, covering the prior calendar year's measurements. This page reflects the 2024 report; a new report will replace it once the utility publishes its next annual update.