Radon in Illinois Homes: How to Test and When

Radon is a radioactive gas that forms in the ground and can seep into homes through cracks in floors, walls, and foundations. Because it is invisible and has no smell, the only practical way to know whether your home has elevated levels is to test.

Illinois’ weather and housing stock—ranging from basements to slab-on-grade homes—mean radon pathways can vary widely even between nearby properties. That’s why experts recommend testing at the address, not relying on neighborhood averages.