Radon and Real Estate in Minnesota
This information from the Minnesota Department of Health (MDH) addresses radon concerns that
may arise during estate transactions. Its intent is to assist buyers and sellers in making informed
decisions about radon. Radon is not regulated in Minnesota, so it is up to homeowners themselves
to decide how much radon is acceptable in their home. Handling radon issues during the sale of a
home is open to negotiation between the buyer and seller. Since a radon problem can be easily
identified and fixed, there is no health-based reason why it should be a "deal breaker".
Why is radon important in Minnesota?
Minnesota's geology contains widespread uranium and radium that supply a constant source of
radon. Many of our houses are also built and operated in ways that increase the likelihood of radon
entry in homes. The MDH estimates that one in three (1/3) Minnesota homes has radon levels that
may pose a large risk to health over many years of exposure. Radon is the leading cause of lung
cancer for non-smokers in the United States. For more information on the health risks from radon
see the MDH fact sheet Radon in Minnesota Homes.
What is radon?
Radon is a naturally occurring gas that enters buildings from the surrounding soil. It is colorless,
odorless, tasteless and radioactive.
How can I find out if a home has a radon problem?
Test results from nearby homes can not be relied upon to predict the radon level in your home. A
properly performed radon test within the house is the only way to find out if a radon problem
exists. Performing such a test on your own is easy, inexpensive, and can be done privately. Such
tests can be conducted prior to a purchase or after moving in.
Radon measurement professionals may be used when an unbiased third party is desired. If a
professional is hired, MDH recommends selecting a professional who is certified by the National
Environmental Health Association (NEHA) or by the National Radon Safety Board (NRSB). Although
tests by certified individuals should be of high quality, they are still subject to the uncertainties
related to the timing and duration of the test (see MDH fact sheet Minnesota Radon Testing and Use
of Test Results).
Contact the MDH Indoor Air Unit for more information on where to obtain low cost radon test kits,
the types of test kits available, how to test your home properly and how to use the results.
How do you test properly?
The goal of radon testing should be to estimate the annual average radon concentration. Since
occupant activities, house operations and weather patterns (daily, short-term and seasonal
variations) can greatly influence the radon level over the short periods of time, the best way to test
a house and evaluate the health risk from radon is to perform a long-term test.
The amount of time available until the closing may place practical constraints on the ability to
measure radon effectively. Short-term testing, which is typically done for a period of 48 hours to 7
days, is less useful than long-term testing.
Short-term tests offer a quick and inexpensive way to "screen" for radon in a home. Short-term
tests cannot measure the annual average level of radon. Decisions on whether or not to mitigate a
home should not be based solely on the results of one short-term test.
Long-term tests more accurately reflect the average amount of radon in the home during the year.
The best way to estimate a year-round average is to test for a full year. If a year-long test can't be
done, the test period should include both heating and cooling seasons. Results from long-term
radon tests can reasonably be used to decide whether or not to mitigate a home.
What do the test results mean?
The United States Environmental Protection Agency (EPA) set a recommended action level for
radon at 4.0 picoCuries/liter (pCi/L) as advice to the public on how to understand their test results.
To use the recommended action level correctly, it should be compared to the annual average level
of radon in a home. If the annual average level of radon in a home is above this action level, EPA
and MDH recommend that steps be taken to lower it. Because any amount of radon carries some
risk, even at or below 4.0 pCi/L, EPA and MDH also recommend considering taking action to lower
radon levels if the annual average level of radon is between 2 and 4 pCi/L. See Minnesota Radon
Testing and Use of Test Results for more detailed advice on the use of test results. This fact sheet
is available by calling MDH or on our website.
Recommendations to Sellers
Consider the benefits of testing your house well before you put it on the market. If you can
demonstrate that radon levels in your home are relatively low based upon the results of a properly
conducted radon test, that may be a positive selling point. It may also save time and last minute
hassles during the selling process. If you find a problem that should be fixed, you will have more
time to get it done and may get a better price than if you wait until you are in the middle of the
sale. If you have the time to conduct a long-term test, you can also ensure that the best possible
information is used for making decisions about the presence of a radon problem and the need for
If you choose to test your home, use a test kit or device from a reputable manufacturer or the
services of a certified radon measurement professional. Ideally, a long-term test should be
performed and you need to begin early enough to complete the test before putting the home on
the market. MDH recommends testing of the lowest livable area in the home. This is defined as a
space which does not have a dirt floor and in which an adult could stand upright. After you test the
house, save the test results and provide these to prospective buyers if they request.
Contact the MDH Indoor Air Unit for more information on how to obtain low cost radon test kits,
how to perform tests properly and how to use the results. The MDH fact sheet Minnesota Radon
Testing and Use of Test Results provides more details on radon testing.
If you have already tested your home, save the test results and provide these to prospective
buyers if requested. If past radon tests were short-term in duration (2 to 7 days), you should
consider performing a long-term test and begin early enough to complete the test before putting
the home on the market. Also, if the home has been remodeled, weatherized, or had changes
made to heating or ventilation (for example, air conditioning or ventilation fans) systems since the
previous radon test was done, MDH recommends retesting to measure current conditions.
Recommendations to Buyers
In Minnesota, it is up to the buyer to decide what they need to know about radon to be comfortable
with the purchase of a home. Prospective buyers should keep in mind that it is inexpensive and
easy to measure radon and a problem can nearly always be fixed at a fairly reasonable cost.
Buyers should also understand that the amount of radon typically found in Minnesota homes does
not pose a significant short-term risk; instead the health concerns result from cumulative exposure
over many years. From a health perspective, radon should not be an obstacle to buying a home
that is otherwise desirable.
If a home has been tested for radon, the buyer must decide if the results of past testing are
acceptable. Issues to consider include the following.
Duration of test. For how many total days was the test conducted? How well does the test period
approximate a year-round test and account for seasonal variations in radon levels? Long-term
tests should span both heating and non-heating seasons. Tests of less than 48 hours are not valid.
Timing of the test. Was it performed during the heating or non-heating season? Short-term tests
performed during the heating season are more likely to overestimate the year-round average.
Short-term tests performed during the non-heating season are more likely to underestimate the
Type of test device used? Was the test device appropriate for the kind of test performed?
Charcoal test kits should not be used for tests greater than 14 days in length.
What area of the house was tested? How does this location reflect your anticipated use
of the home? MDH recommends that homeowners test their own homes in the lowest level that is
occupied on a regular basis.
Was the test kit put in an appropriate location? See test kit instructions and the MDH fact
sheet Minnesota Radon Testing and Use of Test Results.
Who performed the test? If a third party performed the test, were they certified by
either NEHA or NRSB for this activity? This is not a requirement in Minnesota. Certified or not,
the test results are only as good as the procedure and protocols that were followed.
Have structural changes been made to the house? A new test should be done to reflect
current conditions if structural changes were made or heating, ventilation or air conditioning
systems were modified since the test was performed?
What level of radon was found? How does this compare to the level you feel
If a home has not been tested for radon or past testing is not satisfactory, the buyer should decide
if they wish to request radon testing. If such a request is made, it is best to bring it up as early as
When a buyer asks for radon testing prior to a home purchase, MDH recommends specifying the
following conditions (these may be included into the contract if desired).
Who will perform the test
Type of test
Area of the home to be tested
When the test will be done
How results will be shared between parties
Who will pay for testing, and
How the results will be used
Because radon testing during real estate transactions is not required and radon in homes is not
regulated in Minnesota, buyers and sellers are free to negotiate and respond as they choose to the
issue of radon during real estate transaction in this state. This includes any determination of what
radon level needs mitigation and who will pay for it.
What is the role of the real estate professional?
Real estate professionals address many aspects of buying and selling homes. However, their
licensing prohibits them from offering technical advice regarding radon and health risks unless they
are qualified to do so. Instead, they should advise their clients to consult with local health
authorities who work on radon issues, the MDH Indoor Air Unit staff, the U.S. EPA reference
materials, or certified radon professionals.
Why do relocation companies dictate terms of radon testing and interpretation?
Relocation companies have their own policies regarding how to handle radon testing and mitigation
decisions. MDH does not have any involvement with such policies and does not necessarily endorse
them as scientifically based. Sellers and buyers who choose to work with a relocation firm should
recognize that their options regarding radon testing and mitigation may be restricted by the terms
of their agreement with the company.
What can be done to fix a radon problem?
If high levels of radon are found, homeowners can act to lower the amount of radon in their home
and reduce the risks to their family. A number of steps can be taken to lower the amount of radon
in a home. One option is to install a radon reduction (mitigation) system. These are often able to
reduce the annual average radon level to below 2 pCi/L. Radon mitigation professionals can install
appropriate control systems throughout Minnesota. Contact MDH for information regarding radon
Where can I get more information on radon or other indoor air quality issues?
Minnesota Department of Health
Indoor Air Unit
625 Robert St N
PO Box 64975
St. Paul, MN 55164-0975
Phone: 651-201-4601 or 800-798-9050
For questions about this page or indoor air quality, please contact the Indoor Air Unit
at email@example.com, 651-201-4601 or 800-798-9050.
Radon Testing and Real Estate in Minnesota
Where to get EPA approved test kits
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