Groundwater in Shiawassee County contains iron, arsenic, and chloride that well owners should be aware of. These contaminants exceed EPA health standards, making testing and treatment important priorities.
These contaminants come from the Marshall aquifer, a sandstone layer that sits deep below the surface. As groundwater moves slowly through this rock in low-oxygen conditions, iron and arsenic dissolve naturally from the minerals locked inside the stone. Chloride enters from road salt applied to highways above, which seeps down into the aquifer over time.
Groundwater in this county is notably high in iron, which drives much of the water's character. Iron at these levels is common across wells in the county, and the sandstone bedrock here naturally releases this metal as water passes through it.
Wells in Shiawassee County commonly contain arsenic, chloride, and iron at levels above EPA health standards. Arsenic is colorless and odorless--you cannot taste it or detect it--but long-term exposure increases your risk of cancer and heart disease. Chloride at elevated levels can harm people with certain health conditions. High iron in drinking water does not pose direct health risks at the levels seen here, but it deserves attention.
Water in this county shows noticeable quality-of-life impacts from elevated iron and minerals. You will likely see orange-brown staining on sinks, toilets, and laundry. The moderate sodium content contributes to hard water, which can shorten the lifespan of water heaters and dishwashers over time. You may also notice a metallic or slightly salty taste.
We recommend testing your well with a comprehensive metals and minerals panel to know exactly what is in your water, since every well is different and your levels may be higher or lower than what is common in the county. Testing is the only way to understand what treatment your well needs. A comprehensive panel typically costs $200-400 and will identify all three contaminants. Arsenic removal systems using reverse osmosis or specialized filtration paired with iron removal can address these concerns.
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 ⓘ |
|---|---|---|---|---|---|
| Nitrite | 1 | 100% | Low | High ⓘ | |
| Iron | 29 | 86% | Moderate | High | |
| Arsenic | 14 | 64% | Low | High | |
| Chloride | 29 | 28% | Moderate | High | |
| Manganese | 25 | 24% | Moderate | High | |
| Fluoride | 23 | 4% | Moderate |
Moderate
Elevated concentration, not % above limit
|
|
| HFPO-DA (GenX) ⓘ municipal | 4 | 0% | Low | Safe ⓘ | |
| Nitrate | 10 | 0% | Low | Low | |
| PFHxS ⓘ municipal | 4 | 0% | Low | Safe ⓘ | |
| PFNA ⓘ municipal | 5 | 0% | Low | Safe ⓘ | |
| PFOA ⓘ municipal | 5 | 0% | Low | Safe ⓘ | |
| PFOS ⓘ municipal | 4 | 0% | Low | Safe ⓘ | |
| Sulfate | 29 | 0% | Moderate | Low | |
| Hardness | 29 | — | Moderate | Low | |
| PFBS ⓘ municipal | 4 | — | Low | Safe ⓘ | |
| pH | 30 | — | Moderate | Low | |
| Sodium | 29 | — | Moderate | 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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