Radon is a colorless, odorless radioactive gas that seeps up from soil and rock into basements and ground floors. EPA estimates it causes about 21,000 lung cancer deaths a year in the US, making it the leading cause among people who have never smoked. The only way to know your level is to test.
Option 1: a short-term kit ($15-25)
A charcoal canister sits in the lowest lived-in level of your home for two to four days, then goes to a lab in a prepaid mailer. Close windows and outside doors for 12 hours before and during the test. Lab fees are often included; check before you buy.
Option 2: a digital monitor ($55-250)
Monitors show a running average and how levels change with weather, seasons and ventilation. They cost more up front but answer the question repeatedly, which is useful after renovations or before and after mitigation.
Reading the result
- 4 pCi/L or higher: EPA recommends fixing your home.
- 2 to 4 pCi/L: EPA suggests considering a fix; there is no known safe level.
- Below 2: retest every few years, or after major changes to the house.
What mitigation involves
Most systems use sub-slab depressurization: a pipe through the foundation and a quiet fan that vents soil gas above the roof line. Installed cost is typically $800-2,500. Use a certified installer, and retest afterwards. Get free quotes from local installers.
Check your county on the radon zone map, but remember zones describe county averages. High homes exist in every zone.