Radon Testing in Maine: Rules, Rentals, Home Sales and Well Water
Radon Testing in Maine: Rules, Rentals, Home Sales and Well Water
Maine has some of the most detailed radon rules in the country. Homeowners aren’t required to test, but anyone who tests or mitigates radon professionally must be registered with the state. Landlords must test residential rental buildings and give tenants the results. Sellers must disclose known radon on the property disclosure statement, and a test done for a home sale must be performed by an independent registered tester. Maine CDC also recommends testing well water, since radon in water is common in parts of the state. This article explains each rule and how to test your home.
Why radon testing matters in Maine
Radon is a radioactive gas that forms naturally in soil and rock and can build up indoors. Long-term exposure causes lung cancer. Maine CDC reports that at least 25 percent of homes tested in any part of the state have radon problems, regardless of location or how the home was built. Because levels vary from house to house, a test is the only way to know your home’s level. Our article on whether radon maps are useful or misleading explains why location alone can’t answer that question.
The EPA recommends fixing a home at or above 4 pCi/L and considering action between 2 and 4 pCi/L. No radon level is considered completely safe.
Do Maine homeowners have to test for radon?
No. Maine doesn’t require owners of single-family homes to test for radon. You can test your own home with a kit, or you can hire a professional. If you hire someone, Maine law requires that person or firm to be registered with the state.
Maine’s Radon Registration Act requires the state to register firms and individuals who test for radon or who provide services to reduce it. Maine CDC’s guidance says a registered tester must conduct a test unless the owner or occupant does it themselves. In practice, that means a home inspector, contractor or other professional who tests or mitigates radon for you needs a current Maine registration. Ask for it before you hire.
Radon testing for Maine home sales
Maine requires sellers of residential real property to provide a property disclosure statement. Under Title 33, Section 173, that statement must address the presence or prior removal of hazardous materials on the property, and radon is specifically listed. The law doesn’t require a seller to test before listing, so the disclosure reflects what the seller knows.
When radon testing is done as part of a sale, Maine CDC says an independent registered radon tester is required. Buyers, sellers and real estate agents can’t perform the test themselves. That requirement helps protect both sides from disputes over how a test was placed or run. Our guide for real estate agents on radon covers how testing usually fits into a transaction.
If a test comes back high, buyers and sellers commonly negotiate a price credit, a repair before closing or an escrow holdback for mitigation. An older result can also be misleading, because radon changes with the seasons and with changes to the house. Our guide to radon testing in winter vs. summer explains why timing matters.
Radon testing rules for Maine rental properties
Maine is one of the few states that requires radon testing in rental housing. Title 14, Section 6030-D applies to residential buildings rented to tenants, including apartments, college dormitories and nursing homes. Seasonal rentals of 100 days or less are excluded.
When landlords must test
Existing rental buildings had to be tested by March 1, 2014. After that, landlords must retest every 10 years when a tenant requests it, unless a mitigation system is in place and working. New rental buildings must be tested within 12 months after a tenant first occupies the building.
Who can perform the test
A registered radon tester must do the testing in most cases. A landlord may test a building personally only if it meets the state’s criteria. The building can’t have an elevator shaft, an unsealed utility chase or open pathway, or a forced hot air or central air system. It also can’t use private well water unless that water has been professionally tested for radon. Tenants may test their own unit following state rules, or hire a registered tester.
What tenants must be told
Landlords must give tenants written notice within 30 days of receiving test results, or before a new tenant signs a lease. The notice covers the test date and results, whether mitigation has been done, the tenant’s right to test and the risks of radon. Maine CDC’s guidance says tenants sign an acknowledgment that they received the disclosure.
What happens if a rental tests high
If a test shows radon at or above 4.0 pCi/L, either the landlord or the tenant may end the lease or tenancy with at least 30 days’ notice. The law doesn’t require the landlord to mitigate. If the landlord chooses to, the work must be done by a registered mitigation professional. Violations can carry civil fines of up to $250 each, and failing to notify tenants or falsifying results is treated as a breach of the warranty of habitability.
Radon in Maine well water
Many Maine homes rely on private wells, and radon in groundwater is common in parts of the state. When water is used for showers, laundry or dishes, radon escapes into the air, where it adds to indoor exposure. Maine CDC uses 4,000 pCi/L as its Maximum Exposure Guideline for radon in water and says treatment is strongly recommended at about 10,000 pCi/L.
If your home has a private well, test both the air and the water. Water treatment systems for radon, such as aeration units, are different from the soil depressurization systems used for radon in air, so a water problem needs its own fix. Maine CDC also recommends testing private wells for arsenic and uranium, which can occur in the same areas.
Maine’s Gold Standard radon program
In 2021, Maine created the Gold Standard for Radon Testing and Mitigation Initiative, which began July 1, 2022. This is a voluntary recognition program, not a new requirement. Under the statute, participating landlords test every two years and mitigate at or above 4.0 pCi/L, and participating homeowners test air and water, including well water for arsenic and uranium, before selling. The law provides for state coverage of testing costs and the first $600 of mitigation for participants. Program availability depends on state funding, so check with Maine CDC’s radon program before planning around it.
How to test your Maine home
For a valid air test, place the device in the lowest lived-in level of your home, away from drafts, heat sources, high humidity and exterior walls. Keep windows and exterior doors closed for at least 12 hours before the test and throughout it, except for normal entry and exit. A short-term test gives a quick answer, while a long-term test lasting more than 90 days better reflects year-round exposure.
Our radon testing guide walks through the process, our radon test kit comparison covers kits and monitors and our article on what 4.0 pCi/L actually means explains how to read a borderline result. For a well water test, contact a certified laboratory, since water samples need special collection and handling.
Radon readings reported in Maine
Maine homeowners have submitted 65 radon readings to RadonResources.com, from towns including Rumford, Fort Kent, Bangor, York and Hallowell. About 9 in 10 were at or above 4 pCi/L. That share is much higher than the state’s overall rate, because people with elevated results are more likely to share them. It can’t tell you your own level, but it shows that high readings show up across Maine. You can browse radon readings homeowners have reported or visit our Maine radon page for local professionals.
Fixing elevated radon in Maine
The most common fix for radon in air is active soil depressurization, a vent pipe and fan system that draws radon from beneath the foundation and releases it above the roof. Sealing cracks helps the system work, but sealing alone is usually not a dependable fix for significantly elevated radon. In Maine, the contractor must be registered with the state. After installation, a post-mitigation test confirms whether the system worked. Our guide to hiring a certified radon mitigator and our radon contractor checklist cover what to ask before you hire. If a follow-up test is still high, our article on what to do when a post-mitigation test fails walks through the next steps.
Frequently asked questions
Can I test my own home for radon in Maine?
Yes. Homeowners and occupants can test their own homes with a kit, and Maine’s registration requirement doesn’t apply to that. The exception is a home sale. Maine CDC says testing for a sale must be done by an independent registered radon tester, not the buyer, seller or agent.
Do Maine landlords have to fix high radon?
No. Maine law requires landlords to test and to tell tenants the results, but it doesn’t require mitigation. If a test shows 4.0 pCi/L or higher, either the landlord or tenant may end the lease with at least 30 days’ notice. If the landlord mitigates, a registered mitigation professional must do the work.
How do I check whether a radon tester is registered in Maine?
Maine CDC’s radon program maintains information on registered testers and mitigators. You can contact the program at 207-287-5676 or [email protected] to confirm a professional’s registration before you hire them.
What is the radon level for well water in Maine?
Maine CDC uses 4,000 pCi/L as its Maximum Exposure Guideline for radon in water and strongly recommends treatment at about 10,000 pCi/L. These water figures aren’t comparable to the 4 pCi/L action level for air, because only a small share of radon in water ends up in the indoor air.
Using Maine’s rules to your advantage
Maine’s laws give homeowners, buyers and tenants more protection than most states. Registration means professionals have to meet state standards, rental testing means tenants can learn their level and seller disclosure brings known radon into the open. None of it requires a homeowner to test, though, so the decision is still yours. If you’d like help testing your air or water, or with a high result, you can connect with a registered radon professional in Maine.
Sources and further reading
- Maine CDC, Radon Frequently Asked Questions (share of homes, water guideline, testing for sales, registered testers).
- Maine CDC, Rental Building Radon Testing FAQ (rental rules, protocols, tenant acknowledgment).
- Maine Revised Statutes, Title 14, Section 6030-D (landlord testing, notice, lease termination, penalties).
- Maine Revised Statutes, Title 33, Section 173 (seller disclosure of hazardous materials, including radon).
- Maine Revised Statutes, Title 22, Section 773 (registration of radon testers and mitigators).
- Maine Revised Statutes, Title 22, Section 785 (Gold Standard for Radon Testing and Mitigation Initiative).
- U.S. Environmental Protection Agency, A Citizen’s Guide to Radon (action levels, testing guidance).
- RadonResources.com user-submitted radon readings (self-reported and not a representative sample).
This article is for general educational purposes and is not legal or medical advice. Laws and program details can change. Consult a Maine attorney for legal questions, Maine CDC’s radon program for current requirements and a registered radon professional for testing or mitigation.
