Radon is a naturally occurring, invisible and odorless radioactive gas that comes from the breakdown of uranium in soil and rock. It can enter a home through cracks and openings in the foundation, crawlspace or basement.
Radon is found throughout Montana, and any home can have elevated radon levels—regardless of its age, location, foundation type or construction.
Long-term exposure to elevated radon can increase the risk of lung cancer. Because radon cannot be seen, smelled or tasted, testing is the only way to know the radon level in a home.
What Should Montana Home Buyers Know?
A radon test is commonly performed as part of a buyer’s home inspection. It measures radon in picocuries per liter of air, written as pCi/L.
The U.S. Environmental Protection Agency recommends:
- Below 2.0 pCi/L: This is a lower radon level, although the EPA notes that no radon level is considered completely risk-free.
- Between 2.0 and 4.0 pCi/L: Buyers and homeowners may consider mitigation to further reduce exposure.
- 4.0 pCi/L or higher: The EPA recommends taking action to reduce the home’s radon level.
The EPA-recommended action level is 4.0 pCi/L, but a result below that level does not mean radon is absent. Buyers should discuss the test result and appropriate next steps with their home inspector and a qualified radon professional.
Radon Testing During a Montana Real Estate Transaction
Radon testing is often requested as a separate part of the home-inspection process. The Montana Department of Environmental Quality Radon Control Program recommends testing homes during real estate transactions and provides Montana-specific information about test kits, service providers and mitigation.
Testing conditions matter. Buyers should follow the testing professional’s instructions and avoid moving, covering or interfering with the test device while it is collecting measurements.
A home’s location on a radon map—or a neighboring home’s test result—cannot determine the radon level in the specific property being purchased. Individual homes can test differently, which is why the EPA recommends testing rather than relying on geography, age or construction alone.
What Happens if a Home Tests High?
An elevated radon result does not necessarily mean there is something wrong with the home or that a buyer should walk away.
Radon can typically be mitigated. A professional radon mitigation system is designed to draw radon gas from beneath the home and safely vent it outside before it enters the living space.
The appropriate system depends on the home’s foundation and construction. A qualified radon professional can evaluate the property and recommend a suitable mitigation approach.
After a mitigation system is installed, the home should be retested to confirm that radon levels have been reduced. Homeowners should also follow the testing and maintenance guidance provided for the installed system.
Radon Is Manageable
For Montana home buyers, radon testing is an important part of learning about the property. If elevated levels are discovered, buyers can discuss mitigation options with their home inspector, a qualified radon professional and their real estate agent.
The goal is not to make buyers fearful of a home. It is to identify the radon level, understand the available options and make an informed decision while there is still time to address the issue within the transaction.
Official Radon Resources
- Montana DEQ — Radon Control Program
- U.S. EPA — Radon Action Level
- U.S. EPA — Home Buyer’s and Seller’s Guide to Radon
This information is provided as a general educational resource and is not medical, environmental, inspection or legal advice. Buyers and property owners should consult current EPA and Montana guidance and qualified radon professionals regarding testing, results and mitigation for a specific property.
