Is radon a problem in Iowa?
Short answer: Iowa has the highest average indoor radon levels of any U.S. state. The Iowa Department of Public Health estimates that 7 out of 10 Iowa homes have elevated radon. Testing is strongly recommended for every home in Iowa City.
Yes — and Iowa is the worst state in the country for it.
The Iowa Department of Public Health, working with the EPA, has been tracking indoor radon levels for decades. Their data is consistent: the average Iowa home tests at roughly 8.5 pCi/L, more than double the EPA action level of 4.0 pCi/L. By comparison, the national average is around 1.3 pCi/L.
The reason is geological. Iowa sits on glacial till and limestone with naturally elevated uranium content, and our cold winters mean homes are sealed up tight for months at a time, concentrating any radon that does enter.
In Iowa City specifically, expect about 70% of homes to test elevated. Newer construction is not necessarily safer — radon is a soil-gas issue, not a construction issue, and even brand-new homes regularly test above 4.0 pCi/L.
The good news: radon is one of the most fixable indoor air quality issues. A properly installed mitigation system reduces levels by 50–99% and lasts 15+ years with minimal maintenance.