Radon Testing

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

Second test (either short or long-term test)

*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.