Indoor air quality spotlight: radon

IN MAINE, HIGH levels of radon gas occur naturally in our soil and water, a result of the breakdown of the granite upon which Maine sits. Radon is a colorless and odorless gas that gets trapped in buildings that have contact with the earth, such as your home. The Maine Center for Disease Control & Prevention estimates that 33% of Maine homes are likely to have radon levels above the U.S. Environmental Protection Agency’s recommended action level. And in Cumberland County, that estimate rises to 66%. There’s reason to be concerned, as radon is the 2nd leading cause of lung cancer nationwide, and the #1 cause of lung cancer in non-smokers.

Fortunately, it’s fairly simple to test your home for radon. And fall and winter are the ideal time to do it, when windows are closed for the season. If you do find elevated levels of radon in your home, the process of reducing radon to acceptable levels is fairly simple and low cost in most cases.

Fall/Winter are the perfect time to test your home for radon

You can’t tell by looking at your home whether or not it has high radon. Nor can you tell by what type of foundation it has, how old it is, or by your next door neighbor’s test result. The only way to know whether or not your home has high radon is to test it. The Fall and Winter months— when your doors and windows are closed and your heat is on—are the best times of year to test your home for radon.

Testing in “closed conditions” gives you the best assessment of the potential risk to you and your family. If your home has a private well, you will need to test the water, too, since radon can be released from the water into the air.

find a list of all registered radon professionals at or by calling 1-800-232-0842

Testing your home for radon is easy and can be done by you or a registered professional. Homeowners can purchase test kits ($50 or less per test kit) from stateregistered environmental labs—either directly from the lab or at hardware stores and retail lumber outlets. Note: If your home is for sale, and a radon air or water test is going to be done, state law requires the test be done by a registered radon professional. State law also requires radon testing by registered radon professionals in all residential rentals. Find a list of registered testing professionals and environmental labs on the State of Maine’s radon home page: or by calling 1-800-2320842 or 207-287-5698.

At what level should you fix your home?

You should address elevated radon levels if your radon in air level is at or above 4, or if your radon in water level is at or above 10,000. EPA and Maine CDC further recommend you consider fixing your home if your radon in air levels are between 2 and 4.

If your home tests high for radon in air or water, contact a radon professional registered with the State of Maine to install a system in your home to prevent radon exposure to you and your family. In most cases, available methods make it possible to get radon in air levels to 2 or below; and radon in water levels to 4,000 or below. Talk with your radon professional about available options, costs, and efficacy. Homeowners can also call the Maine Radon Section to discuss options: 1-800-232-0842

Build radon out of your new home

If you are planning to build a new home, installing radon preventive features during construction is:

Cheaper: All the key features of the radon system can be installed in your new home for $500-$1000, compared to $1500 or more for a retrofit system.

More effective: Installing radon preventive features during construction will make that system more effective at reducing radon in air levels to 2 or below.

More energy efficient: Radon preventive features installed during construction have straighter pathways, allowing for the potential that natural forces alone (without an electric fan) will keep radon levels at 2 or below.

Part of Maine building codes: Installing radon preventive features during construction is easy, but it is important to pay attention to details. To help you get it right the first time, the Maine building codes include requirements for radon systems being installed during new construction.

Further guidance on how to build radon out of your new home is available through your local Codes official or the State Radon Section.

Don’t neglect radon when doing renovations or energy upgrades

Because radon is a gas, any renovation that changes how air flows around and through your home can impact your radon levels. Always test your air both before and after your renovation to make sure your home has acceptable levels of radon. G&HM

These tips are provided by the Maine Indoor Air Quality Council, a nonprofit organization dedicated to the creation of healthy, environmentally sustainable indoor environments. For more information about indoor air quality in your home, school or workplace, contact the Council at or 207-626-8115.


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This article is reprinted from the fall 2016 issue of Green & Healthy Maine Homes. Subscribe today!