The result: the American Lung Association reports 71.6% of Iowa homes test above the EPA’s 4 pCi/L action level. Linn County houses regularly come back at 7–14 pCi/L on initial tests. The EPA estimates radon causes about 21,000 lung-cancer deaths per year — second only to smoking.
Mitigation isn’t guesswork. A properly designed sub-slab depressurization (SSD) system pulls radon out from beneath your slab before it ever enters living space and vents it above the roofline. Installed correctly, post-mitigation tests routinely drop to 0.5–1.5 pCi/L — well below the action level and below typical outdoor air.