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How to read your radon results
US results are reported in picocuries per liter (pCi/L).
| Result | What EPA says |
|---|---|
| 4.0 pCi/L or higher | Fix your home. 4.0 pCi/L is EPA’s action level. |
| 2.0–3.9 pCi/L | Consider fixing. EPA says there is no known safe level and radon below 4 still poses some risk. |
| Below 2.0 pCi/L | No EPA fix recommendation. The national indoor average is about 1.3 pCi/L. EPA says you may want to test again in the future, and retest a lower level if you start living there. |
EPA’s steps: if a short-term test reads 4 or higher, follow up with a long-term test or a second short-term test. Fix if the long-term result, or the average of the two short-term tests, is 4 or higher. Home sales follow EPA’s separate Home Buyer’s and Seller’s Guide.
Source: EPA A Citizen’s Guide to Radon. EPA’s 4 pCi/L action level equals 150 Bq/m³ (EPA action level).