How often should you test your home for radon?

The EPA recommends testing your home for radon at least every two years, and every year if you already have a mitigation system in place. Radon is a naturally occurring radioactive gas that comes from the breakdown of uranium in soil, and it’s the second leading cause of lung cancer in the U.S. behind smoking.

Testing is the only way to know your level because radon is invisible and has no smell or taste. You can buy a DIY test kit online or at a hardware store for around $15–$30. Short-term tests sit in your lowest lived-in level for 2–7 days, then you mail them to a lab. If the result is 4 pCi/L or higher, the EPA says you should install a mitigation system.

You should also retest any time you renovate or make structural changes to your home, since shifting the foundation or adding insulation can change how radon enters.