MDH recommends that all Minnesota homeowners test their homes for radon. A radon test is the only way to find out how much radon is in your home. You can test your home yourself or hire a licensed radon measurement professional. Hiring a licensed radon measurement professional is recommended when an unbiased, third party is needed, such as in a real estate transaction. The result from a properly performed radon test will help you decide if you need to reduce your home's radon level.
Download a printable version of the brochure on radon testing Radon: A brief guide on how to keep your home safe from radon (PDF)
Types of radon test kits
There are two basic types of radon tests:
- Short term - a short term test measures radon levels for 2-7 days and is a quick way to screen a home for radon. When you test for radon you should start with a short-term test.
- Long term - a long-term test measures radon levels for a minimum of 90 days. They are the best way to estimate the annual average of radon in the home. Long-term testing should include both heating and non-heating seasons.
How often should I test for radon?
- All Minnesota homes should be tested for radon and then retested every 2-5 years (save your test results).
- Test after you make changes to the foundation, heating, cooling or ventilation. Consider testing before a major remodeling project to determine if radon mitigation should be added into the project.
- Retest after adding a radon mitigation system to make sure it is working properly.
Where can I get a radon test kit?
A radon test kit costs between $5 and $30, depending on the type of kit. Some test kits may also require an analysis fee paid after mailing the kit to the lab.
- Air Chek, Inc. a manufacturer of short term radon test kits. Minnesota residents receive a discount. Order online: Air Chek.
- Radonova a manufacturer of long term radon gas test kits. Minnesota residents receive a discount. Order online: Radonova.
- Many local agencies distribute radon information and some distribute radon test kits to their residents, see list of Local Radon Contacts.
Radon testing guidelines
- Instructions - Read the instructions that come with the radon test kit and fill out the information that is needed.
- Time of year - Short-term tests can be completed any time of the year, but the heating season is the best time to test. Long-term tests should include some of the heating and non-heating seasons.
- Weather - Weather can affect the radon levels in the home. If there is severe or unusually windy weather, wait to perform a short-term test.
- Test location - Test the lowest level of the home that is regularly used. For example, if you spend more than 10 hours a week in the basement, MDH recommends testing the basement. For real estate transactions, test the lowest level of the home such as the basement.
- Test placement - Place the test kit at least 20 inches above the floor where it will not be disturbed. Keep away from drafts and 3 feet from exterior walls and windows. Keep away from high humidity areas like kitchens, baths, and laundry rooms. Keep away from heat areas like fireplaces and furnaces.
- Home Conditions - Short-term radon tests require closed-house conditions. This means keeping all windows and exterior doors closed, except for normal entry and exit.
How to perform a short term radon test
Radon test results
You should complete two tests before deciding to install a radon mitigation system, except when a professional uses a continuous radon monitor. Start with an initial, short-term test.
Initial short-term test
|0 - 1.9||Retest every 2-5 years with a short-term test|
|2 - 8||Perform a follow-up long-term test|
|Greater than 8||Perform a follow-up short-term test|
Second test (either short or long-term test)
|0 - 1.9||Retest every 2-5 years*|
|2 - 3.9||Consider a radon mitigation system|
|4 or greater||Highly recommend a radon mitigation system|
*If the initial test was 8 pCi/L or above, consider performing a long-term test.
Deciding to mitigate should be based on the long-term test results or the average of the two short-term tests. In real estate transactions, the decision to mitigate should be based on a continuous monitor test or two short-term tests done side by side and averaged.