Under 2.0 pCi/L
Keep the report. Retest at a sensible interval and after major changes to the home.
Report-first answer
What Does My Radon Test Result Mean?
Use the number from your report to choose the next step. This page explains the national threshold; it does not turn a county average into a verdict about your home.
The short answer
EPA recommends fixing a home when the radon level is 4.0 pCi/L or higher. A result below 4.0 is not an all-clear: keep the report and decide whether follow-up or long-term testing would reduce uncertainty for your home and situation.
2.0–3.9 pCi/L
Below the main action threshold, but not zero risk. A follow-up or long-term test can make the decision clearer.
4.0–7.9 pCi/L
This reaches EPA’s action threshold. If it came from a short-term test, CDC says to take a second short- or long-term test; use the average if both tests are short-term.
8.0 pCi/L or higher
Treat this as a high reading. Preserve the report and prioritize the next test or reduction decision, especially when a home transaction has a deadline.
One number is not the whole instruction
- A short-term result at or above 4.0
- Take a second short- or long-term test. If both are short-term, use their average for the decision.
- A long-term result at or above 4.0
- CDC says this supports contacting a licensed professional for a radon reduction system.
- After a home is fixed
- Retest a few months later to check whether the level was reduced.
This summary follows CDC’s homeowner testing guidance. Your report instructions and applicable state or local requirements still control.
Before you act, keep the details that change the answer
- The number and unit: record the pCi/L exactly as reported.
- Test type and duration: short-term and long-term tests answer different uncertainty questions.
- Location: note the lowest lived-in level and where the device was placed.
- Dates and test conditions: retain the complete report rather than a screenshot of the number alone.
Buying or selling a home?
Do not jump from one number to a price claim. Build a documented repair, credit, or retest decision around the inspection report and the transaction deadline.
Use the failed-inspection decision guide →Result questions
Common questions about a radon number
What does a 4.0 pCi/L radon result mean?
It reaches EPA’s recommended action level. The next step depends on the test type: CDC advises a second test after a short-term result, while a long-term result at or above 4.0 supports contacting a licensed reduction professional.
Is a 2.5 pCi/L radon result bad?
It is below the main 4.0 pCi/L action level, but it is not a promise that no action is ever appropriate. EPA says homeowners may consider fixing a home between 2.0 and 4.0 pCi/L; a long-term test can make the home’s average clearer.
What should I do with an 8.0 pCi/L radon result?
Preserve the full report and act promptly on the test or reduction path. If it was a short-term test, follow the confirmation guidance; if the result is part of a transaction, document the deadline and the agreed repair, credit, or retest path.
Can an EPA radon zone or county average explain my result?
No. Maps and county records are useful local context, but testing is the only way to know the level in a specific home. Browse local context separately.
Sources
The 4.0 pCi/L action threshold comes from EPA guidance. CDC explains why testing the individual home matters; a local zone or county record cannot replace it.