Groundwater in Oakland County contains arsenic, radon, iron, and other contaminants that well owners should monitor. Several of these contaminants exceed EPA health standards, making this a serious concern.
These contaminants come from the Marshall aquifer, a sandstone layer beneath the county. As groundwater moves slowly through this rock in low-oxygen conditions, naturally occurring metals like iron and arsenic dissolve into the water. Radon is a radioactive gas released from the rock itself. Road salt applied to highways also enters the groundwater, contributing to elevated chloride levels.
Groundwater in Oakland County is notably high in iron, which drives much of the water's mineral character. Iron concentrations in the sandstone are released as water sits in contact with the rock over long periods. These iron-rich conditions are common across most wells tested in the county.
Wells in Oakland County commonly contain arsenic, radon, chloride, and perfluorinated compounds (PFOA and PFOS) at levels that exceed EPA health standards. Arsenic is a poison that builds up in your body over time and increases the risk of cancer and organ damage. Radon is a radioactive gas that comes from rock deep underground and can damage your lungs with long-term exposure. These contaminants pose serious health risks that require attention.
Wells in this county also show elevated iron and moderate sodium levels that affect daily life. High iron causes orange-brown staining on sinks, toilets, and laundry that is hard to remove. The combination of these minerals can shorten the lifespan of water heaters and dishwashers over time.
We recommend testing your well because every well is different and your water 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. A comprehensive metals and minerals panel typically costs $200-400 and will tell you exactly what you are dealing with. Treatment options like reverse osmosis systems or arsenic-specific removal filters can address multiple 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 | 393 | 74% | High | High | |
| Arsenic | 138 | 22% | High | High | |
| Manganese | 270 | 21% | High | High | |
| Chloride | 453 | 8% | High | Moderate | |
| Radon | 29 | 3% | Moderate |
Moderate
ⓘ
Elevated concentration, not % above limit
|
|
| Nitrate | 381 | 1% | High | Low | |
| PFHxS ⓘ municipal | 198 | 1% | High | Low | |
| PFOS ⓘ municipal | 198 | 1% | High | Low | |
| PFOA ⓘ municipal | 198 | 1% | High | Low | |
| Sulfate | 451 | 0% | High | Low | |
| Fluoride | 381 | 0% | High | Low | |
| HFPO-DA (GenX) ⓘ municipal | 196 | 0% | High | Low | |
| Lead | 93 | 0% | Moderate | Low | |
| Nitrite | 178 | 0% | High | Low | |
| PFNA ⓘ municipal | 198 | 0% | High | Safe | |
| Uranium | 94 | 0% | Moderate | Low | |
| E. coli | 4* | 0% | Low | Low ⓘ | |
| Hardness | 461 | — | High | Low | |
| PFBS ⓘ municipal | 198 | — | High | Low | |
| pH | 503 | — | High | Low | |
| Sodium | 355 | — | High | Low | |
| Total Coliform | 4* | 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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