DIY Radon Test: How to Do It Right

A do-it-yourself radon test kit is cheap and easy, but the result is only as good as the setup. Follow the instructions that come with your kit first. These are the common rules, based on state health department testing guidance.

1. Pick the right room

• Test the lowest lived-in level of the home. If you use the basement, or could use it as living space, test there.
• Use a bedroom, living room or similar space. Avoid kitchens, bathrooms, laundry rooms and crawl spaces.

2. Place the kit correctly

• At least 20 inches off the floor
• At least 1 foot from exterior walls and about 3 feet from doors and windows
• Away from heat sources, electronics, direct sunlight and drafts
• Somewhere it won’t be moved or bumped

3. Keep the house closed

For short-term tests (under four days), keep windows and outside doors closed for at least 12 hours before and during the test. Normal coming and going is fine. Run heating and air conditioning normally, but avoid whole-house fans, window fans and fireplaces.

4. Pick your timing

• Most short-term kits run 2 to 4 days; long-term kits run 90 days or more.
• Avoid starting a short-term test right before severe storms or very windy weather.
• Winter, when the house is closed up anyway, is a natural time to test.

5. Finish properly

• Write down the exact start and end times and the room.
• Seal the kit and send it to the lab right away. Most kits need to arrive within a few days to be accurate.

Common mistakes

• Testing an unused upper floor instead of the lowest lived-in level
• Opening windows during the test
• Leaving the kit on the floor or near an outside door
• Waiting a week to mail it

Got your result?

Here’s how to read your radon test result. Buying or selling a home? A professional test is usually the better choice. See radon and real estate.