Groundwater in Sanilac County contains iron, arsenic, and sulfate at levels that exceed EPA health standards and warrant immediate attention. These contaminant levels are serious enough to require testing and potential treatment of your well.
These contaminants come from the Marshall sandstone rock layer beneath the county. As groundwater moves slowly through this rock, iron and arsenic dissolve naturally from the stone itself. Sulfate and chloride also come from ancient mineral layers and road salt that seep down into the groundwater over time.
Groundwater in this county is moderately hard and notably high in iron. Iron concentrates here because it occurs naturally in the sandstone and dissolves when oxygen levels drop deep underground. These mineral characteristics are common across wells in Sanilac County, though individual wells vary in how much iron and hardness they contain.
Wells in Sanilac County commonly contain arsenic, chloride, and sulfate at levels exceeding EPA health standards. Arsenic is a serious concern because long-term exposure can increase the risk of cancer and damage to organs. Chloride at elevated levels can harm kidneys and is especially risky for people on low-sodium diets. Sulfate can cause digestive problems.
The high iron levels in county wells stain sinks, toilets, and laundry with reddish-brown marks that are hard to remove. You may also notice a metallic taste in the water. The moderate hardness means some white crusty buildup on fixtures is possible. Over time, mineral deposits can build up inside pipes and water heaters.
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 well so it can be properly treated. A comprehensive metals and minerals panel typically costs $200-400 and will identify all contaminants present. Treatment options like reverse osmosis systems or water softeners can address these concerns once you know your specific results.
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 ⓘ |
|---|---|---|---|---|---|
| Arsenic | 28 | 57% | Moderate | High | |
| Iron | 35 | 54% | Moderate | High | |
| Manganese | 35 | 29% | Moderate | High | |
| Nitrate | 18 | 6% | Moderate | Moderate | |
| Sulfate | 34 | 3% | Moderate | Low | |
| Chloride | 34 | 3% | Moderate | Low | |
| Fluoride | 34 | 0% | Moderate | Low | |
| HFPO-DA (GenX) ⓘ municipal | 12 | 0% | Low | Safe | |
| Lead | 14 | 0% | Low | Low | |
| Nitrite | 18 | 0% | Moderate | Low | |
| PFHxS ⓘ municipal | 12 | 0% | Low | Safe | |
| PFNA ⓘ municipal | 12 | 0% | Low | Safe | |
| PFOA ⓘ municipal | 12 | 0% | Low | Safe | |
| PFOS ⓘ municipal | 12 | 0% | Low | Safe | |
| Radon | 5 | 0% | Low | Low ⓘ | |
| Uranium | 11 | 0% | Low | Low | |
| E. coli | 2* | 0% | Low | Safe ⓘ | |
| Hardness | 34 | — | Moderate | Low | |
| PFBS ⓘ municipal | 12 | — | Low | Safe | |
| pH | 36 | — | Moderate | Low | |
| Sodium | 34 | — | 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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