Iron, radon, and arsenic are present in St. Croix County groundwater. Iron and radon exceed EPA health standards and require attention from well owners.
The rock layers beneath this county naturally contain iron and release radon as radioactive elements in the stone break down over time. Water moving through these layers picks up iron from the rock itself. Arsenic also occurs naturally in the bedrock. These contaminants are common across wells throughout the county.
Groundwater in this county is moderately hard, driven by elevated iron levels. Iron concentrates in the water because it is present in the underlying rock and dissolves as water passes through. Most wells in St. Croix County show this iron signature.
Wells in St. Croix County commonly contain iron and radon at levels that exceed EPA health standards. Radon is a radioactive gas that increases the risk of lung cancer when breathed in over time. Iron itself does not create health risks, but radon exposure is a serious concern that deserves attention.
County well water is moderately hard, and the elevated iron creates visible problems. You will see rust-colored staining on sinks, fixtures, and laundry. The water may taste metallic. Hard water also leaves white scale buildup in pipes and on fixtures, which can shorten the lifespan of water heaters and dishwashers.
We recommend a comprehensive water test to find out what is actually in your well, since every well is different and your water could have higher or lower levels than what is common here. Testing is the only way to know exactly what needs treatment. A comprehensive metals and minerals panel costs between $200 and $400. Iron removal systems and radon aeration can address these concerns once testing shows what you are dealing with.
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 | 140 | 17% | High | High | |
| Manganese | 134 | 13% | High | Moderate | |
| Nitrate | 132 | 8% | High | Moderate | |
| Arsenic | 18 | 0% | Moderate | Low | |
| Chloride | 138 | 0% | High | Low | |
| Fluoride | 124 | 0% | High | Low | |
| HFPO-DA (GenX) ⓘ municipal | 28 | 0% | Moderate | Safe | |
| Lead | 18 | 0% | Moderate | Low | |
| Nitrite | 115 | 0% | High | Low | |
| PFHxS ⓘ municipal | 28 | 0% | Moderate | Safe | |
| PFNA ⓘ municipal | 28 | 0% | Moderate | Safe | |
| PFOA ⓘ municipal | 28 | 0% | Moderate | Safe | |
| PFOS ⓘ municipal | 28 | 0% | Moderate | Safe | |
| Radon | 7 | 0% | Low | Low ⓘ | |
| Sulfate | 139 | 0% | High | Low | |
| Uranium | 18 | 0% | Moderate | Low | |
| E. coli | 3* | 0% | Low | Safe ⓘ | |
| Hardness | 142 | — | High | Low | |
| PFBS ⓘ municipal | 28 | — | Moderate | Safe | |
| pH | 140 | — | High | Low | |
| Sodium | 111 | — | High | Low | |
| Total Coliform | 3* | 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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