Radon guide
What radon levels mean
How to interpret radon test results, decide when to retest, and know when to compare mitigation providers.
Updated .
Radon levels are often reported in picocuries per liter in U.S. data and becquerels per cubic meter in Canadian or international guidance. A single result is a starting point, not the whole story, because levels can change with weather, ventilation, test length, home operation, and season. Use the result to decide whether you need a retest, a longer measurement, or a mitigation conversation.
Reading the result
Higher results usually mean the home should be evaluated for mitigation. Borderline results may call for another test, especially when the first test was short-term or the home was under unusual conditions during testing.
| Result situation | Sensible next step |
|---|---|
| No current result | Start with a test before requesting mitigation quotes. |
| Borderline or surprising result | Ask whether a follow-up test or longer measurement makes sense. |
| Elevated result | Compare mitigation providers and ask how they would design and verify a system. |
| Real estate deadline | Ask providers about report timing, quote timing, and post-install documentation. |
Why local context matters
Homes in the same city can test differently because foundation conditions, soil, ventilation, and construction details vary from property to property. Local context matters, but the house-specific test result matters more than a city average or map estimate.
What to ask a provider
Ask whether the provider recommends additional testing, what mitigation system type may fit the foundation, whether post-install testing is included, and which certification or license applies to the person doing the work. If any field is unknown in a directory profile, treat it as a question to confirm before hiring.
Next step
Use the Radon Mitigation Companies to compare testing and mitigation providers, then ask how they verify results after any system is installed. For deeper context on how listings are gathered and ranked, read the methodology.