Ann Arbor Water System water quality
Ann Arbor, MI · serves 123,851 people (26,050 connections) · Surface water · Local government · EPA ID MI0000220
Data: U.S. EPA · How we read the data · How we check it
Summary
No federal limits exceeded in EPA data.
- PFAS
- Detected, below limit3 of 29 PFAS found at least once. All averages below the federal limits.
- Lead
- Below action level2.3 ppb (parts per billion) at the 90th percentile: 9 in 10 homes sampled were at or below it. Action level 15 ppb, falling to 10 ppb in Nov 2027. Monitoring period ending Dec 2023. Your home's pipes can make yours higher.
- Violations
- None health-basedNo health-based violations since 2016.
- Built before 1986, or not sure what your service line is made of? Check your service line and test your tap. Utility data can't show your pipes.
- Tested your own tap? Compare your result with these numbers. Moving? Compare this system with another.
- Read Ann Arbor Water System's annual water quality report (Consumer Confidence Report). It lists every regulated contaminant tested and is usually on the utility's website or mailed with your bill, and you can also request it at (734) 794-6000. EPA: how to find it.
PFAS (“forever chemicals”)
EPA UCMR 5: 1 entry point tested Mar 2023 to Dec 2023. "Average" is the highest entry-point average (non-detects counted as zero), the way EPA compares UCMR 5 results to the limits. ppt = parts per trillion. These results do not determine compliance.
| Contaminant | Highest average |
|---|---|
| PFOA Not detected Limit 4 ppt | – |
| PFOS Not detected Limit 4 ppt | – |
| PFHxS Not detected Limit 10 ppt | – |
| PFNA Not detected Limit 10 ppt | – |
| HFPO-DA (GenX) Not detected Limit 10 ppt | – |
| Hazard Index (a combined score for PFHxS, PFNA, GenX and PFBS, where above 1 is over the limit) Not detected Limit 1 | – |
| PFBS Not detected Guideline 2,000 ppt | – |
| PFBA Detected, below limit Guideline 6,000 ppt | 1.53 ppt |
| PFHxA Detected, below limit Guideline 3,000 ppt | 0.88 ppt |
| PFPeA Detected, no limit | 2.7 ppt |
Michigan has its own PFAS limits. PFNA 6 ppt (this system's highest average: not detected), PFOA 8 ppt (this system's highest average: not detected), PFHxA 400000 ppt (this system's highest average: 0.88 ppt), PFOS 16 ppt (this system's highest average: not detected), PFHxS 51 ppt (this system's highest average: not detected), PFBS 420 ppt (this system's highest average: not detected), HFPO-DA 370 ppt (this system's highest average: not detected). State compliance is judged on the state's own sampling, so ask the utility or the state program whether it meets them.
29 PFAS tested, 3 detected at least once. "Not detected" means below EPA's reporting limit (about 2 to 20 ppt depending on the chemical), not proven zero. PFAS not listed were not detected. The limits for PFHxS, PFNA, GenX and the Hazard Index were proposed for rescission in May 2026. That proposal is not final. Systems have until 2029 to meet the limits.
Lithium
Not detected in 4 samples (reporting limit 9 ppb). About lithium.
Lead and copper
Latest 90th percentile: 2.3 ppb lead (Jan 2021 – Dec 2023). Below action level
Highest since 2016: 3 ppb (Dec 2017).
| Monitoring period | Lead (90th pct.) |
|---|---|
| Jan 2021 – Dec 2023 | 2.3 ppb |
| Jan 2018 – Dec 2020 | 1 ppb |
| Jan 2015 – Dec 2017 | 3 ppb |
Earlier results (9)
| Jan 2012 – Dec 2014 | 2 ppb |
| Jan 2009 – Dec 2011 | 4 ppb |
| Jan 2006 – Dec 2008 | 8 ppb |
| Jan 2003 – Dec 2005 | 2.62 ppb |
| Jan 2000 – Dec 2002 | 5.75 ppb |
| Jan 1997 – Dec 1999 | 6.1 ppb |
| Jan 1996 – Dec 1996 | 5.1 ppb |
| Jul 1994 – Jun 1995 | 6.1 ppb |
| Jul 1993 – Jun 1994 | 7.6 ppb |
Lead comes from pipes and fixtures, not the source water, so it varies home to home. The 90th percentile means 9 in 10 sampled homes were at or below it. More on lead.
Violations
1 unresolved monitoring or reporting violation: Lead and copper rule revisions.
Health-based violations mean a contaminant exceeded a limit or a required treatment step was missed. Monitoring and reporting violations mean required tests or reports were late or missing, so the water's quality during that time is unknown. The total includes every violation in EPA's records, most of them paperwork.
Earlier EPA testing (2013–2020)
| Contaminant | Highest | Guideline |
|---|---|---|
| Manganese | 1.61 ppb | 300 ppb |
| Chromium-6 | 0.27 ppb | – |
| Vanadium | 0.54 ppb | 21 ppb |
| Strontium | 0.17 ppm | 1.5 ppm |
| Molybdenum | 6 ppb | 40 ppb |
| Chlorate | 400 ppb | 210 ppb |
Where it serves
ZIP codes the system reported serving: 48103, 48104, 48105, 48106, 48107, 48108, 48109, 48113
Nearby utilities
- Ypsilanti Community Utility Authority Ypsilanti · 6 mi
- Canton Township Water System Canton charter · 13 mi
- City of Novi Novi · 19 mi
- Livonia Water System Livonia · 20 mi
- Dundee Water System Dundee · 22 mi · PFAS above limit
- Dearborn Heights Water System Dearborn Heights · 23 mi
Questions
Is Ann Arbor Water System water safe to drink?
Ann Arbor Water System has no health-based violations since 2016. EPA testing found no PFAS above the federal limits. Federal data can't tell you about your own pipes: lead comes from service lines and plumbing, so test your tap if your home was built before 1986. For the official word, read the utility's annual Consumer Confidence Report.
Does Ann Arbor Water System water have PFAS?
Yes. EPA's 2023–2025 testing of Ann Arbor Water System found 3 PFAS at least once. None of the averages were above the federal limits.
What is the lead level in Ann Arbor Water System water?
The most recent 90th-percentile lead result for Ann Arbor Water System is 2.3 ppb, for the period ending Dec 2023. The federal action level is 15 ppb, falling to 10 ppb in November 2027. The 90th percentile means 9 in 10 homes sampled were at or below this number. Individual homes can be higher.
Check these numbers yourself
Every figure on this page comes from public EPA records. You don't have to take our word for it:
- EPA's own report for MI0000220: violations, enforcement and inspections, straight from EPA.
- EPA UCMR 5 data: the PFAS and lithium results (search the file for PWSID MI0000220).
- EPA SDWIS download: the lead results, population and violation records we use.
- The utility's annual water quality report (Consumer Confidence Report): ask Ann Arbor Water System at (734) 794-6000, or see EPA's guide to finding it.
Found something that doesn't match? Tell us and we'll check it against EPA's records. How we check our data.
Source: U.S. EPA drinking water records and PFAS testing (UCMR 5). How we read the data.