The homeowner’s reference
How long does a radon test take? 5 things to know before booking
A short-term radon test measures for 2–90 days, depending on the device. A long-term test runs for more than 90 days. Preparation, shipping and the time needed to issue a report are separate, so a two-day measurement does not necessarily mean results in two days.
Sources: CDC: Testing Your Home for Radon.
1. Choose the test type before setting a deadline
Ask the tester which device they will use and how long it must stay in place. CDC describes short-term tests as 2–90 days and long-term tests as more than 90 days. A longer measurement captures more of the variation in a home's radon level.
If you are buying a home, tell the tester your inspection deadline before booking. Ask for the setup date, collection date and expected report date as three separate dates.
Sources: CDC: Testing Your Home for Radon; EPA: Home Buyer's and Seller's Guide to Radon (2024, PDF).
2. Allow time for the house to be ready
EPA's home-buyer guidance calls for closed-house conditions for at least 12 hours before a 2–4 day test and throughout the measurement. Keep windows and outside doors closed except for ordinary entry and exit. Get the tester's written instructions for ventilation and equipment before the appointment.
For example, a test scheduled to begin Tuesday morning may require preparation on Monday evening. Follow the instructions for the particular test and any applicable state requirements.
Sources: EPA: Home Buyer's and Seller's Guide to Radon (2024, PDF).
3. Leave the device in place for the full measurement
A convenient pickup time should not shorten the required exposure. EPA's real-estate guide specifies a minimum of 48 hours, with some devices needing longer. Record the agreed start and finish times and leave the device where the tester placed it.
Tell the tester if the device is moved or testing conditions change. Ask whether the measurement remains usable before relying on the report.
Sources: EPA: Home Buyer's and Seller's Guide to Radon (2024, PDF).
4. Ask when the report will arrive
A kit that needs laboratory analysis has another step after measurement ends. Follow its return instructions promptly. Fort Collins' radon program notes that short-term kits are time sensitive and that mailing delays or incorrect handling can lead to rejected results.
Before choosing a kit or appointment, ask who returns the device, whether shipping is included, and when the laboratory or tester expects to send the report. There is no single turnaround time for every provider.
Sources: City of Fort Collins: Radon.
5. Leave room for the next decision
The first report may lead to follow-up testing or a discussion with a mitigation professional. Read the result and the recommended next step together; do not plan a transaction around the assumption that one appointment will settle every question.
Keep the report, test dates and device information. If another measurement is recommended, ask which test to use and how its timing fits your deadline.
Sources: CDC: Testing Your Home for Radon.
Before you book
- What device will be used, and how long must it measure?
- When do closed-house conditions begin?
- Who collects or returns the device?
- When should I expect the written report?
- Who will explain any recommended follow-up?
Find a credentialed provider
Browse the testing listings for your city or county. Match the provider's credential number and testing scope with the official source before booking.
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Testing instructions and requirements depend on the test, building and jurisdiction. Use the linked agency guidance and your qualified professional’s instructions for your situation.