New to Radon Testing? Start Here
Radon Testing: the few things that matter most, and the mistakes that catch people out early.
Testing indoor air for radon, a radioactive gas from soil and rock that you cannot see, smell or taste.
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 speak to a doctor" below apply to you.
Why bother
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.
Start here
Just these two to begin with. The rest can wait.
- Test every home, whatever its age or location; neighbors' results do not predict yours
- Use a short-term test kit, then a follow-up test if the result is 4 pCi/L or higher
Then add these
After that, these.
- Hire a qualified radon mitigation contractor if levels are high; a common fix is a vent pipe and fan system
- Retest after mitigation and every 2 years afterward, and after major renovations
- Ask your state radon program about low-cost test kits
The numbers, in one place
| Measure | Figure |
|---|---|
| EPA action level | 4 pCi/L or higher: fix the home |
| Between 2 and 4 pCi/L | EPA recommends considering a fix |
| Homes with elevated radon | about 1 in 15 US homes, per EPA |
| Lung cancer deaths linked to radon | about 21,000 a year, per EPA |
| Where to test | the lowest lived-in level of the home |
Common early mistakes
- Assuming new homes or homes without basements are radon-free
- Testing with windows open or during a strong storm, which can skew results
- Smoking, which greatly increases the lung cancer risk from radon
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: Common Questions Answered
- Radon Testing: Just the Figures
- 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 speak to 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.
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.
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