Well Water in Winnebago County: What to Test and Why

Winnebago County groundwater contains iron, radon, sulfate, chloride, and lead at levels that exceed EPA health standards. These contaminants are present at concerning concentrations that well owners should address.

The deep limestone and sandstone rock layers beneath this county naturally release iron, sulfate, and chloride into groundwater as water sits in contact with the stone over time. Radon seeps into the water from radioactive elements found in the rock itself. Some chloride may also come from road salt and other surface sources that have worked down into the aquifer.

Groundwater in this county is very hard, driven by elevated calcium and magnesium from the limestone bedrock below. As water moves slowly through these mineral-rich rock layers, it dissolves these elements and carries them into wells. Very hard water is widespread across wells throughout the county.

Wells in Winnebago County commonly contain chloride, iron, lead, radon, and sulfate at levels that exceed EPA health standards. Chloride at elevated levels can harm people with heart disease or high blood pressure. Iron above health standards raises health concerns for infants and people with certain conditions. Lead is particularly dangerous for children and pregnant people because it damages the brain and nervous system. Radon is a radioactive gas that enters groundwater naturally and increases the risk of lung cancer when you breathe it in over time.

The county has very hard water, which creates white, crusty scale buildup on pipes, fixtures, and appliances. You may notice rust-colored or brown staining on clothes, sinks, and toilets from the elevated iron. Hard water makes it harder to clean dishes and laundry, and soap becomes less effective. Very hard water can shorten the lifespan of water heaters and dishwashers because scale clogs the systems inside them.

Testing is the only way to know what is actually in your well, since every well is different and your water may have higher or lower levels than what is common in the county. We recommend a comprehensive metals and minerals panel that tests for all these concerns--this typically costs between $200 and $400. Water softeners can address hardness, and iron removal systems or radon treatment through aeration may help depending on what testing shows.