Well owners in Fond du Lac County should be aware of six contaminants detected in local groundwater: chloride, iron, manganese, nitrate, radon, and sulfate. Several of these--chloride, iron, manganese, radon, and sulfate--exceed EPA health standards, which means they warrant attention.
The deep limestone and sandstone rock beneath Fond du Lac County naturally holds these minerals and dissolves them as groundwater moves slowly through the stone over many years. Chloride and sulfate come directly from the rock itself. Radon, a radioactive gas, seeps into the water from uranium decay in the bedrock. Nitrate can enter from agricultural land use in the county. Iron and manganese also come from the rock layers underground.
Groundwater in Fond du Lac County is very hard, driven mainly by calcium and magnesium from the limestone below, and it also contains elevated iron. These minerals dissolve into the water as it passes through the bedrock. Very hard water with elevated iron is common across wells throughout the county.
Wells in Fond du Lac County commonly contain chloride, nitrate, radon, and manganese at levels that exceed EPA health standards. Chloride at elevated levels can harm people with high blood pressure or heart disease. Nitrate is especially dangerous for infants and can interfere with how blood carries oxygen. Radon is a radioactive gas that increases lung cancer risk when breathed in over time. Manganese can affect the brain and nervous system with long-term exposure.
The county has very hard water, which creates practical problems around the home. You will see white, crusty scale buildup inside pipes, on faucets, and in appliances. Iron in the water stains clothes, sinks, and bathtubs with rust-colored marks. Hard water makes soap less effective for cleaning and can shorten the lifespan of water heaters and dishwashers. The water may also taste slightly metallic or have a faint sulfur odor.
We recommend testing your well water, since every well is different and yours may have higher or lower levels than what is common in the county. A comprehensive metals and minerals panel typically costs $200-400 and is the only way to know what is actually in your water so it can be properly treated. Testing reveals your specific contamination profile so you can choose the right solution. Iron removal systems and water softeners can address the mineral concerns found in county wells.
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 | 113 | 56% | High | High | |
| Radon | 5 | 20% | Low | High ⓘ | |
| Manganese | 106 | 16% | High | High | |
| Sulfate | 119 | 6% | High | Moderate | |
| Nitrate | 57 | 4% | Moderate |
Moderate
Elevated concentration, not % above limit
|
|
| Chloride | 120 | 1% | High | Low | |
| Arsenic | 9 | 0% | Low | Low ⓘ | |
| Fluoride | 107 | 0% | High | Low | |
| HFPO-DA (GenX) ⓘ municipal | 24 | 0% | Moderate | Safe | |
| Lead | 9 | 0% | Low | Low ⓘ | |
| Nitrite | 38 | 0% | Moderate | Low | |
| PFHxS ⓘ municipal | 24 | 0% | Moderate | Low | |
| PFNA ⓘ municipal | 24 | 0% | Moderate | Low | |
| PFOA ⓘ municipal | 24 | 0% | Moderate | Low | |
| PFOS ⓘ municipal | 24 | 0% | Moderate | Safe | |
| Uranium | 15 | 0% | Moderate | Low | |
| Hardness | 120 | — | High | Low | |
| PFBS ⓘ municipal | 24 | — | Moderate | Low | |
| pH | 119 | — | High | Low | |
| Sodium | 88 | — | 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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