Radon, arsenic, and chloride are present in Sauk County groundwater. Radon exceeds EPA health standards and is the primary concern; arsenic and chloride are detected but at levels below health thresholds.
Radon comes from uranium naturally present in the deep rock layers beneath the county. As groundwater sits in contact with these rocks over long periods, radon gas enters the water. Arsenic and chloride occur naturally in these same rock formations and dissolve into the water as it moves slowly through the layers.
Groundwater in this county is moderately hard, with calcium and magnesium from the limestone and sandstone that hold the water. These minerals accumulate because water stays in contact with the rock for extended periods before reaching wells. Moderate hardness is common across wells in Sauk County.
Radon shows up above EPA health standards in wells across Sauk County. Radon is a radioactive gas that comes from rocks deep underground. When you drink water with elevated radon, the gas enters your body and can damage your lungs and increase cancer risk over time. The health risk from radon is a serious concern that needs attention.
County wells are moderately hard, which means you might see some chalky white scale buildup inside pipes and on fixtures over time. You may also notice rust-colored staining on sinks or toilets. Hard water can make soap and shampoo less effective, and the mineral buildup can shorten the lifespan of water heaters and dishwashers.
We recommend testing your well water to find out what you actually have. Every well is different, and your well may have higher or lower radon levels than what is common in the county. Testing is the only way to know what is in your water so it can be properly treated. A comprehensive metals and minerals panel typically costs between $200 and $400. Radon aeration systems and water softeners are both effective treatment options.
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 ⓘ |
|---|---|---|---|---|---|
| Radon | 3 | 33% | Low | High ⓘ | |
| Manganese | 103 | 21% | High | High | |
| Iron | 104 | 18% | High | High | |
| Nitrate | 80 | 11% | Moderate | Moderate | |
| Arsenic | 16 | 0% | Moderate | Low | |
| Chloride | 104 | 0% | High | Low | |
| Fluoride | 95 | 0% | Moderate | Low | |
| HFPO-DA (GenX) ⓘ municipal | 38 | 0% | Moderate | Safe | |
| Lead | 19 | 0% | Moderate | Low | |
| Nitrite | 51 | 0% | Moderate | Low | |
| PFHxS ⓘ municipal | 38 | 0% | Moderate | Low | |
| PFNA ⓘ municipal | 38 | 0% | Moderate | Safe | |
| PFOA ⓘ municipal | 38 | 0% | Moderate | Low | |
| PFOS ⓘ municipal | 38 | 0% | Moderate | Safe | |
| Sulfate | 104 | 0% | High | Low | |
| Uranium | 15 | 0% | Moderate | Low | |
| PFBS ⓘ municipal | 38 | — | Moderate | Low | |
| pH | 110 | — | High | Low | |
| Sodium | 66 | — | Moderate | Low | |
| Hardness | 105 | — | High | 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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