top of page

Consumer's Guide to Radon Reduction.


Radon is the leading cause of lung cancer for non-smokers and the second leading cause of lung cancer in the general population. The Surgeon General and EPA recommend testing for radon and reducing radon in homes that have high levels. Fix your home if your radon level is confirmed to be 4 picocuries per liter, pCi/L, or higher. Radon levels less than 4 pCi/L still pose a risk, and in many cases may be reduced. If you smoke and your home has high radon levels, your risk of lung cancer is especially high.


For people who have tested their home for radon and confirmed that they have elevated radon levels — 4 pCi/L or higher. This booklet can help you.


The North Carolina state radon office can provide information on how to test your home or how to locate a qualified radon professional. EPA's A Citizen's Guide to Radon and the Home Buyer's and Seller's Guide to Radon have information on radon testing. Both documents are available at



How Radon Enters Your Home

Radon is a naturally occurring radioactive gas produced by the breakdown of uranium in soil, rock, and water. Air pressure inside your home is usually lower than pressure in the soil around your home's foundation. Because of this difference in pressure, your home acts like a vacuum, drawing radon in through foundation cracks and other openings.

Radon also may be present in well water and can be released into the air in your home when water is used for showering and other household uses. In most cases, radon entering the home through water is a small risk compared with radon entering your home from the soil. In a small number of homes, the building materials — such as granite and certain concrete products — can give off radon, although building materials rarely cause radon problems by themselves. In the United States, radon gas in soils is the principal source of elevated radon levels in homes.



What Do Your Radon Test Results Mean?

The U.S. Congress has set a long-term goal that indoor radon levels be no more than outdoor levels; about 0.4 pCi/L of radon is normally found in the outside air. EPA recommends fixing your home if the results one long-term test or the average of two short-term tests show radon levels of 4 pCi/L or higher. With today's technology, radon levels in most homes can be reduced to 2 pCi/L or below. You may also want to consider fixing if the level is between 2 and 4 pCi/L.

A short-term test remains in your home for two days to 90 days, whereas a long-term test remains in your home for more than 90 days. All radon tests should be taken for a minimum of 48 hours. A short-term test will yield faster results, but a long-term test will give a better understanding of your home's year-round average radon level.

The EPA recommends two categories of radon testing. One category is for concerned homeowners or occupants whose home is not for sale; refer to EPA's "A Citizen's Guide to Radon" for testing guidance. The second category is for real estate transactions; refer to EPA's "Home Buyer's and Seller's Guide to Radon," which provides guidance and answers to some common questions.


When you are buying or selling a Home.

When you are buying or selling a home and need to make decisions about radon, consult EPA's "Home Buyer's and Seller's Guide to Radon." If you are selling a home that has a radon reduction system, inform potential buyers and supply them with information about your system's operation and maintenance. If you are building a new home, consider that it is almost always less expensive to build radon-resistant features into new construction than it is to fix an existing home that has high radon levels. Ask your builder if he or she uses radon-resistant construction features. Your builder can refer to EPA's document "Building Radon Out: A Step-by-Step Guide On How to Build Radon-Resistant Homes," or your builder can work with a qualified contractor to design and install the proper radon reduction system. To find a qualified contractor, contact the NC radon office.


All homes should be tested for radon and elevated radon levels should be reduced. Even new homes built with radon-resistant features should be tested after occupancy to ensure that radon levels are below 4 pCi/L. If you have a test result of 4 pCi/L or more, you can have a qualified mitigator easily add a vent fan to an existing passive system to further reduce the radon level in your home.

bottom of page