Radon Mitigation in Wausau, WI
Wausau sits in Marathon County, in the granite belt of north-central Wisconsin. The same uranium-bearing bedrock that gives the region its quarries and rock outcrops also breaks down into radon, and here that radon turns up in two places: the soil gas that seeps into homes and the water drawn from private wells. Marathon County is EPA Radon Zone 1, the higher of the two EPA categories that apply in Wisconsin (predicted average indoor level at or above 4 pCi/L), the EPA's higher screening category. Whether a high reading just surfaced before a sale or you are testing ahead of winter, Badger State Radon connects Wausau homeowners with independent local radon professionals. We are a free matching service, not a contractor, and this page lays out what radon looks like here and what to do about it.
The granite belt and radon in Wausau
Marathon County is EPA Radon Zone 1, the higher of the two EPA categories that apply in Wisconsin (predicted average indoor level at or above 4 pCi/L), cited to the EPA Map of Radon Zones. The local picture is shaped by granite-belt geology that also raises well-water radon for homes on private wells. Radon is a naturally occurring radioactive gas with no color, odor, or taste, formed as uranium in soil and rock breaks down; it enters a house through foundation cracks, sump openings, and, in well-water homes, through the tap. Long-term exposure is the leading cause of lung cancer among people who do not smoke, according to the EPA and the Surgeon General. WI DHS puts about one in 10 Wisconsin homes above 4.0 pCi/L, and Zone 1 counties tend to run higher, per WI DHS. Because Zone 1 is a countywide screening designation, your street and even your neighbor's house can read differently, so testing your own home is the only reliable step.
Radon in your Wausau well water
North-central Wisconsin's granitic geology is exactly the setting where well-water radon matters most. Radon dissolved in groundwater leaves the water when you shower, run the dishwasher, or fill a glass, adding to the air you breathe: about 10,000 pCi/L of radon in water adds roughly 1 pCi/L to indoor air. The concern is private wells, since municipal systems are treated and aerated before delivery. Wisconsin DNR suggests considering treatment when water tests above 4,000 pCi/L of radon, and points homeowners to aeration (about $3,500) or granular activated carbon, with a call to the DNR before installing. If your home is on a private well, a water radon test is worth adding to your air test. See radon in water and the deeper radon in well water guide, and check the WI DNR radon in water page for the details.
Testing your Wausau home
The regional Radon Information Center serves Marathon County, and statewide 17 Radon Information Centers offer kits for about $15 including lab analysis. A short-term charcoal test takes just a few days and suits a home sale, while a long-term test gives a better year-round average. Winter is peak testing season in Wisconsin, since closed-up homes let radon build. If a short-term test comes back at or above 4.0 pCi/L, the EPA recommends confirming with a follow-up test. A private-well home can run a water radon test alongside the air test. The full rundown is on the radon testing page.
Mitigation and cost
If your air level is high, the common fix is active sub-slab depressurization: a pipe and a continuously running fan that draw soil gas from under the foundation and vent it above the roofline. Wisconsin DHS estimates a contractor-installed system typically costs $1,000 to $2,000, with Wausau homes falling in that range depending on foundation type and design; ongoing cost is mainly a few dollars a month for the fan. Sealing cracks alone is not a fix. When the problem is radon in the water instead, treatment is handled at the well side. Learn how systems work on the radon mitigation page. The independent professionals we match you with can hold the voluntary NRPP or NRSB credentials; we do not perform the work or hold any certification ourselves. For the statewide picture, the Wisconsin radon guide ties air and water radon together.