Radon follow-up test planner
A first radon test often raises the question “now what?” This planner applies EPA’s published decision steps to your result.
Your next step
Pick your test type and enter the result. We will apply EPA’s published follow-up steps.
Based on EPA’s A Citizen’s Guide to Radon (2016) and Home Buyer’s and Seller’s Guide to Radon (2018). Your state may have additional rules for real estate testing.
EPA’s testing sequence in brief
EPA’s Citizen’s Guide to Radon lays out a simple path. Start with a short-term test, placed in the lowest lived-in level of the home. If the result is 4 pCi/L or higher, do a follow-up test rather than acting on one snapshot. A long-term follow-up gives a better idea of your year-round average; a second short-term test is quicker. EPA recommends fixing the home if the long-term result is 4 pCi/L or higher, or if the average of your first and second short-term tests is 4 pCi/L or higher.
Why a second test
Radon levels change from day to day and season to season. They tend to be higher in cold months when the house is closed up and the warm air inside draws soil gas in through the foundation. Rain, wind, and even how often doors are opened make a difference. A single short-term reading can land high or low by chance. The follow-up evens that out before you spend money on a mitigation system.
Tests for a home sale
Real estate deals rarely allow three months for a long-term test. EPA’s Home Buyer’s and Seller’s Guide describes options that give results within days, such as two short-term tests running at the same time or a continuous radon monitor, with the decision based on the average. Many states also require that real estate tests be done by a credentialed professional. See radon when buying or selling a home.
After a fix
Retest after a mitigation system is installed to confirm it worked, and periodically after that. EPA’s guidance also suggests retesting if you renovate, change your heating or air conditioning system, or start using a lower level (such as a finished basement) as living space.