Radon Test Kits

A radon test kit is a passive detector, often charcoal or alpha-track, that you place in your home for a set period and mail to a lab. Short-term kits run 2 to 90 days, commonly 2 to 7, while long-term kits run over 90 days and better reflect your yearly average.

How to use a kit correctly

• Check whether the lab fee and return postage are included in the price.
• Follow closed-house conditions for short-term tests: windows and outside doors closed except for normal entry for 12 hours before and during the test.
• Place it in the lowest lived-in level, about 20 inches or more above the floor, away from drafts, kitchens and bathrooms.
• Record start and end times exactly, and mail it promptly, since charcoal kits have strict timing.
• Follow up: EPA suggests a second test if the first result is 4 pCi/L or higher.

For ongoing monitoring after testing or mitigation, see Digital Radon Detectors.

FAQs

How accurate are home radon test kits?

Lab-analyzed kits from certified providers are accurate when used correctly, but results depend on following instructions: closed-house conditions, correct placement, exact timing and prompt mailing. Short-term tests capture only a snapshot, so EPA recommends follow-up testing before deciding on mitigation when results are high.

Short-term or long-term radon test?

Short-term tests give a quick answer in days and are good for screening or home sales. Long-term tests over 90 days give a better picture of your year-round average, since radon varies with seasons. Many homeowners start with a short-term test, then confirm with a long-term test or a second short-term test.

What should I do if my radon test is high?

If a short-term test shows 4 pCi/L or more, EPA recommends a follow-up test. If confirmed, contact a qualified radon mitigation contractor. Common fixes involve sub-slab depressurization with a vent pipe and fan, which can typically reduce levels substantially. Retest after mitigation.