Radon Testing: Common Questions
Testing indoor air for radon, a radioactive gas from soil and rock that you cannot see, smell or taste.
Last revised
Radon Testing: the questions people actually ask, answered from published guidance.
Key takeaways
- EPA action level: 4 pCi/L or higher: fix the home
- Between 2 and 4 pCi/L: EPA recommends considering a fix
- Most useful single change: Test every home, whatever its age or location; neighbors' results do not predict yours.
- Commonest mistake: Assuming new homes or homes without basements are radon-free.
- See a doctor if any of the signs under "When to get help" below apply to you.
What is Radon Testing?
Testing indoor air for radon, a radioactive gas from soil and rock that you cannot see, smell or taste.
Why does it matter?
Radon is the second leading cause of lung cancer in the US and the leading cause among people who have never smoked, and testing is the only way to know your level.
EPA action level for Radon Testing?
4 pCi/L or higher: fix the home.
Between 2 and 4 pCi/L for Radon Testing?
EPA recommends considering a fix.
Homes with elevated radon for Radon Testing?
About 1 in 15 US homes, per EPA.
Lung cancer deaths linked to radon for Radon Testing?
About 21,000 a year, per EPA.
What is the single most useful thing to do?
Test every home, whatever its age or location; neighbors' results do not predict yours.
What is the most common mistake?
Assuming new homes or homes without basements are radon-free.
When should I see a doctor?
See your doctor about lung cancer screening and any symptoms if you have lived with high radon, especially if you smoke or used to. See your doctor for a cough that will not go away, coughing up blood, chest pain or unexplained weight loss, and call 911 for severe trouble breathing or coughing up large amounts of blood.
Related topics
- Air Quality: What the Evidence Actually Says (Respiratory Health)
- Carbon Monoxide During Power Outages: What the Evidence Actually Says (Heat, Cold and Weather Safety)
- Sun Protection: What the Evidence Actually Says (Skin Health)
- Reducing Cancer Risk: Sorting the Evidence From the Noise (Cancer Awareness)
Where to go next
- Radon Testing: Just the Figures
- Radon Testing: What Published Guidance Supports
- Radon Testing — the reference entry
- Environmental Health: The Complete Guide
- What the Guidance Really Says About Mold at Home
- What the Guidance Really Says About Drinking Water and Private Wells
When to get help
See your doctor about lung cancer screening and any symptoms if you have lived with high radon, especially if you smoke or used to. See your doctor for a cough that will not go away, coughing up blood, chest pain or unexplained weight loss, and call 911 for severe trouble breathing or coughing up large amounts of blood.
Where this comes from
- EPA — A Citizen's Guide to Radon
- National Cancer Institute — Radon and Cancer
How this page was put together
Every figure, recommendation and warning above is taken from the guidance named in Where this comes from. Nothing on this page is inferred, summarized or generalized beyond what those bodies publish: where they give a number, it is their number, and where they are silent, so are we. Pages are rebuilt whenever the underlying record changes. Sign-off by a named clinician, where it has happened, is shown at the top of the page along with the date.
Medical disclaimer
This article is general information, not medical advice. It cannot account for your own history, medication or circumstances. Always speak to your doctor, pharmacist or another qualified health professional before making changes that affect your treatment, and never delay seeking medical advice because of something you have read here. In an emergency, call 911.
