Groundwater in Washtenaw County contains manganese, iron, sulfate, chloride, and radon. These contaminants exceed EPA health standards and warrant well testing.
The Marshall aquifer beneath this county is a sandstone formation that naturally releases iron and manganese into groundwater as water moves slowly through it. Chloride and sulfate enter from road salt applied to highways and from natural minerals in the rock that dissolve over time.
Groundwater in this county is high in iron, which is the mineral that drives its aesthetic character. Iron concentrates in the water as groundwater sits in contact with the sandstone aquifer for extended periods. This characteristic is common across wells in Washtenaw County.
Wells in Washtenaw County commonly contain several contaminants that exceed EPA health standards. Chloride, radon, and sulfate all show up at levels of concern in county groundwater. Radon is a radioactive gas that enters drinking water from rocks underground and increases lung cancer risk over time. Manganese and iron, while present, can harm children's brain development and cause other health effects with long-term exposure.
Beyond health risks, the mineral content in county wells affects daily life. High iron levels stain sinks, toilets, and laundry orange-brown and can give water a metallic taste. Manganese creates dark brown or black stains on fixtures. These minerals also build up scale inside pipes and water heaters, which can shorten the lifespan of appliances like dishwashers and hot water tanks over time.
We recommend testing your well water through a state-certified lab. Every well is different, and your well may have higher or lower levels than what is common in the county. Testing is the only way to know what is actually in your water so you can treat it properly. Because multiple contaminants exceed standards here, a comprehensive metals and minerals panel is recommended, which typically costs $200-400. Treatment options like oxidation filters or point-of-entry systems can address several contaminants at once.
Not sure if your well is affected? Get certified results in 5–7 days.
Test Your Well Water with Tap Score →| Contaminant | Samples ⓘ | % Above MCL ⓘ | Distribution ⓘ | Confidence ⓘ | Risk ⓘ |
|---|---|---|---|---|---|
| Iron | 215 | 80% | High | High | |
| Manganese | 65 | 32% | Moderate | High | |
| Arsenic | 45 | 22% | Moderate | High | |
| Chloride | 225 | 4% | High |
Moderate
Elevated concentration, not % above limit
|
|
| Sulfate | 220 | 3% | High | Low | |
| Nitrate | 204 | 0% | High | Low | |
| Fluoride | 69 | 0% | Moderate | Low | |
| HFPO-DA (GenX) ⓘ municipal | 36 | 0% | Moderate | Safe | |
| Lead | 31 | 0% | Moderate | Low | |
| Nitrite | 48 | 0% | Moderate | Low | |
| PFHxS ⓘ municipal | 36 | 0% | Moderate | Safe | |
| PFNA ⓘ municipal | 36 | 0% | Moderate | Safe | |
| PFOA ⓘ municipal | 36 | 0% | Moderate | Safe | |
| PFOS ⓘ municipal | 36 | 0% | Moderate | Safe | |
| Radon | 11 | 0% | Low | Low ⓘ | |
| Uranium | 28 | 0% | Moderate | Low | |
| E. coli | 2* | 0% | Low | Low ⓘ | |
| Hardness | 225 | — | High | Low | |
| PFBS ⓘ municipal | 36 | — | Moderate | Safe | |
| pH | 232 | — | High | Low | |
| Sodium | 74 | — | Moderate | Low | |
| Total Coliform | 2* | 0% | Low | Low ⓘ |
MCL = Maximum Contaminant Level (EPA limit for public water; used as benchmark for private wells). Distribution shows % of sampled wells in each concentration band. Methodology.
* Microbial contaminants (E. coli, coliform) reflect only samples from the last 10 years.
Data shows potential risk — a certified test confirms whether your water is affected.
Order a Tap Score Test →Population-level CDC data. Not individual risk prediction.
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