Radon Test, Test Kits and Mitigation: What to Do About a High Reading

Updated November 1, 2026 · General information, not medical advice

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The short answer: Testing is the only way to know your radon level. EPA recommends testing all homes below the third floor, and fixing your home at 4 pCi/L (150 Bq/m³) or higher. It says to consider fixing between 2 and 4 pCi/L. If your reading is high, follow up with a second test, then call a certified radon mitigation contractor.

Radon is a natural radioactive gas that can build up in any home. EPA says it is a leading cause of lung cancer, and it estimates nearly 1 out of every 15 U.S. homes has an elevated level. Got a high number on a home inspection? Planning a basement bedroom or a nursery? This site explains the steps in plain words, using EPA and CDC guidance.

Start here: what does your radon result mean?

Enter your result in pCi/L or Bq/m³ and the kind of test. See what EPA guidance says to do next.

Open the radon result checker

Guides

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Not medical advice. This page repeats EPA and CDC guidance in plain words. Follow your state radon program and a certified radon professional for decisions about your home, and talk to a doctor about health concerns.

Common questions

What radon level is a problem?

EPA recommends fixing your home at 4 pCi/L (150 Bq/m³) or higher and says to consider fixing between 2 and 4 pCi/L. It also says no level of radon is safe and that levels below 4 pCi/L still pose some risk.

How do I test my home for radon?

Use a radon test kit or hire a qualified tester. EPA says to put a short-term kit in the lowest lived-in level, in a room you use regularly but not the kitchen or bathroom, at least 20 inches off the floor, with windows and outside doors closed.

Should I test a basement bedroom or nursery?

EPA says to test in the lowest level of the home that could be used regularly, and to test the area before and after finishing an unfinished basement.

Can I fix radon myself?

EPA recommends hiring a qualified radon mitigation contractor, because you could actually increase your radon level or create other hazards without the right equipment and knowledge. If you are thinking about doing it yourself, EPA says to contact your state radon office first.

Related guides

Sources
  1. U.S. EPA: A Citizen’s Guide to Radon (EPA 402/K-12/002)
  2. U.S. EPA: Home Buyer’s and Seller’s Guide to Radon (EPA 402/K-24/001, March 2024 revision)
  3. U.S. EPA: Consumer’s Guide to Radon Reduction: How to Fix Your Home (EPA 402/K-10/005, December 2016)
  4. U.S. EPA: Health Risk of Radon
  5. CDC: About Radon

Free printable: Radon Test Day Checklist

EPA's testing steps in one page, plus what your result means. Download the one-page PDF now, or get it by email along with a short series of five helpful emails.

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