A practical radon test plan for homeowners
Test the lowest lived-in level, read the kit instructions closely, and use the result to decide what needs confirmation or mitigation.
Radon is a radioactive gas that can enter buildings from soil and can accumulate indoors. Neighboring homes, a home’s age, or a real-estate test do not establish today’s level in your home. EPA recommends testing all homes below the third floor.
A short-term kit can be a useful screen; a longer test can better reflect changing conditions. Use an accredited or state-approved method, follow closed-home instructions exactly, and keep the result with the home’s maintenance records.
The short answer
Radon cannot be seen or smelled. Testing is the only way to know the level in a particular home, and a result should be followed according to EPA and local program guidance.
Find the state radon program
Start with your state or tribal radon office for local testing options, laboratory requirements, and mitigation credential information. Local geology matters, but every individual home still needs its own test.
Choose short or long-term testing intentionally
A short-term test is often faster when a decision is urgent. A long-term test better reflects seasonal change. Use the instructions and EPA follow-up table rather than treating every result as final.
Set up and record the test
Write down the kit ID, start and end time, floor, room, closed-building conditions, and any unusual event. Place it only where the manufacturer specifies and return it to the lab on time.
Confirm when the result calls for it
EPA provides follow-up testing recommendations based on the initial level and test duration. Do not average unrelated tests or substitute a neighbor’s result for your own home.
Keep mitigation measurable
If mitigation is installed, retain the contract, system label, and post-install test. A future retest and any fan service should be planned as part of normal home records, not forgotten after the first result.
Put the guide to work
Field notes
- Choose the correct level
- Place the test in the lowest level that could be regularly occupied, not necessarily the deepest utility space. Follow the kit’s placement directions for distance from drafts, exterior doors, and moisture.
- Do not improvise conditions
- Short-term tests often require closed-building conditions. Open windows, moving the device, testing beside a sump, or ignoring the required time can make a result harder to interpret.
- Read the number with the method
- The action decision depends on the measured level and testing duration. EPA recommends considering mitigation at 4 pCi/L or higher and considering action between 2 and 4 pCi/L; follow current state guidance too.
- Use qualified mitigation
- A mitigation system is a building intervention, not an air freshener. Select a qualified contractor, obtain a post-mitigation test, and retain the system and test records for future owners and service.
- Result-to-next-step worksheet
- Keep the initial number, the test type and duration, the room and level, the kit instructions, and the laboratory report together. Then use EPA’s follow-up guidance for that result rather than treating a short-term screen, a neighbor’s test, and a later retest as interchangeable evidence.
- Protect the test conditions
- Do not relocate a test to make a room look better, place it in a kitchen or bath, or run unusual ventilation simply because the kit is out. If the required conditions were interrupted, note it and ask the testing program whether a new test is the more reliable choice.
Make the next step useful
Put this guide on your home plan
Know when to call a professional. Stop if work involves active gas leaks, damaged service wiring, structural movement, unsafe heights, suspected contamination, or a problem you cannot confidently isolate.
Editorial review and sources
Reviewed by: Smart Homeowners Editorial Desk
Last reviewed: August 25, 2026
Original Smart Homeowners editorial; not adapted from a third-party article.
