Granite Countertops and Radon in Iowa: What Actually Matters

Every few years a story about radioactive granite makes the rounds, and in Iowa the question lands differently, because radon here is a genuine issue. Iowa's public health department reports that the state has one of the highest shares of homes above the EPA's action level of 4 picocuries per liter, and the whole state is in the EPA's highest-risk radon zone. The source is the ground: radon gas comes out of the soil and rock under the house and gets into basements through the floor and walls. Granite is a natural stone, and some slabs do contain traces of uranium that can release a small amount of radon. The EPA's position is that the existing data don't show that the granite commonly sold for countertops significantly increases indoor radon, and that the soil under the house is the principal source. In practice, that means the useful step for an Ames homeowner isn't to avoid granite, it's to test the house: a short-term test kit costs little, the Iowa Radon Hotline (1-800-383-5992) can point you to one, and if the result is 4 pCi/L or more, a licensed mitigation contractor can fix it. If you'd rather skip the question entirely, quartz is an engineered alternative with a consistent look; see quartz installation or granite installation to compare.