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SESK: Stuff Everyone Should Know · sesk.info/home-a-radon-4pci

At what radon level does EPA recommend you fix your home?

4 pCi/L or higher.

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  1. 10 pCi/L or higher
  2. 4 pCi/L or higher ✔
  3. 1 pCi/L or higher

Why: EPA recommends fixing your home if the level is 4 picocuries per liter or higher. Levels below 4 still pose some risk, and in many cases can be reduced.

Huh, didn't know that: EPA says the average indoor radon level is about 1.3 pCi/L and the average outdoor level is about 0.4 pCi/L.

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Why did the noble gas cry? Because all his friends argon.
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References

Answer: 4 pCi/L or higher. EPA recommends fixing your home if the level is 4 picocuries per liter or higher. Levels below 4 still pose some risk, and in many cases can be reduced.

  1. EPA: A Citizen's Guide to Radon (2016) www.epa.gov/sites/default/files/2016-12/documents/2016_a_citizens_guide_to_radon.pdf
    Fix your home if your radon level is 4 picocuries per liter (pCi/L) or higher.
    Checked 2026-10-10.

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