Radon is not something most New Glarus homeowners think about until they buy a house, sell a house or hear a troubling story from someone who tested too late.

But in Wisconsin, it is a real concern. The Wisconsin Department of Health Services says about 1 in 10 homes in the state has high radon levels, and testing is the only way to know whether a home is affected.

Radon is a naturally occurring radioactive gas released from rock, soil and water. It can enter homes through foundation cracks, sump pits, gaps around pipes and other openings, then build up indoors, especially in basements and lower living areas.