Groundwater in Shiawassee County contains nitrite, iron, and arsenic. These contaminant levels are concerning, with arsenic, chloride, fluoride, iron, manganese, and nitrite all exceeding EPA health standards.
These contaminants come from the rock layers beneath the county. Iron and manganese dissolve naturally as groundwater moves slowly through the Marshall aquifer sandstone. Arsenic is locked inside the rock itself and releases into water over time. Nitrite may enter from fertilizer use on agricultural land common in this area.
Groundwater in this county is very hard, driven by high levels of calcium and magnesium from the limestone and rock layers below. Iron concentrations are also elevated, adding to the mineral load. These characteristics are common across wells throughout Shiawassee County.
Wells in Shiawassee County commonly contain arsenic, chloride, fluoride, iron, manganese, and nitrite at levels exceeding EPA health standards. Arsenic is a poison that builds up in your body over years of drinking and can increase your risk of cancer and other serious illnesses. Manganese can harm children's brain development and learning. Fluoride, chloride, and nitrite also pose health concerns with long-term exposure. Iron and nitrite at elevated levels can affect your overall health.
The mineral content in county wells creates significant quality-of-life problems. Iron causes orange-brown staining on sinks, toilets, and laundry. The water is extremely hard, which means scale buildup inside pipes and appliances--shortening the lifespan of water heaters and dishwashers. You may notice the water tastes metallic or bitter, and soap does not lather well.
We recommend testing your well through a certified lab, since 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 well so it can be properly treated. Because multiple analytes exceed health standards here, a comprehensive metals and minerals panel is recommended and typically costs $200-400. Treatment options like reverse osmosis systems or arsenic-specific removal paired with iron filters 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 ⓘ | |
| 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 | |
| Nitrate | 10 | 0% | Low | 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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