The EPA recommends that you know what the indoor radon level is in any home you are considering buying.  Ask the seller for their radon test results.  If the home has a radon-reduction system, ask the seller for information they have about the system.

If the home has not yet been tested, you should have the house tested.

If you are having a new home built, there are features that can be incorporated into your home during construction to reduce radon levels.

These radon testing guidelines have been developed specifically to deal with the time-sensitive nature of home purchases and sales, and the potential for radon device interference.  These guidelines are slightly different from the guidelines in other EPA publications which provide radon testing and reduction information for non-real estate situations.

This guide recommends three short-term testing options for real estate transactions.  The EPA also recommends testing a home in the lowest level which is currently suitable for occupancy, since a buyer may choose to live in a lower area of the home than that used by the seller.

a. Radon has been found in homes all over the U.S.

Radon is a radioactive gas that has been found in homes all over the United States. It comes from the natural breakdown of uranium in soil, rock and water, and gets into the air you breathe. Radon typically moves up through the ground to the air above, and into your home through cracks and other holes in the foundation. Radon can also enter your home through well water. Your home can trap radon inside.

Any home can have a radon problem, including new and old homes, well-sealed and drafty homes, and homes with or without basements. In fact, you and your family are most likely to get your greatest radiation exposure at home. That is where you spend most of your time.

Nearly one out of every 15 homes in the United States is estimated to have an elevated radon level (4 pCi/L or more).  Elevated levels of radon gas have been found in homes in your state.

b. The EPA and the Surgeon General recommend that you test your home.

Testing is the only way to know if you and your family are at risk from radon. The EPA and the Surgeon General recommend testing all homes below the third floor for radon.

You cannot predict radon levels based on state, local, or neighborhood radon measurements.  Do not rely on radon test results taken in other homes in the neighborhood to estimate the radon level in your home.  Homes which are next to each other can have different radon levels.  Testing is the only way to find out what your home's radon level is.

In some areas, companies may offer different types of radon service agreements.  Some agreements let you pay a one-time fee that covers both testing and radon mitigation, if needed.

If you are thinking of buying a home, you may decide to accept an earlier test result from the seller, or ask the seller for a new test to be conducted by a qualified radon tester.  Before you accept the seller's test, you should determine the results of previous testing by finding out:

who conducted the previous test (the homeowner, a radon professional, or some other person);

where in the home the previous test was taken, especially if you may plan to live in a lower level of the home.  For example, the test may have been taken on the first floor.  However, if you want to use the basement as living space, test there, too;

what, if any, structural changes, alterations, or changes in the heating, ventilation, and air conditioning (HVAC) system have been made to the house since the test was done.  Such changes may affect radon levels.

If you accept the seller's test, make sure that the test followed the Radon Testing Checklist.

If you decide that a new test is needed, discuss it with the seller as soon as possible.

b. If the home has not yet been tested for radon...

Make sure that a radon test is done as soon as possible. Consider including provisions in the contract specifying:

where the test will be located;

who should conduct the test;

what type of test to do;

when to do the test;

how the seller and the buyer will share the test results and test costs (if necessary); and

when radon mitigation measures will be taken, and who will pay for them.

Make sure that the test is done in the lowest level of the home suitable for occupancy. This means the lowest level that you are going to use as living space which is finished or does not require renovations prior to use. A state or local radon official or qualified radon tester can help you make some of these decisions. If you decide to finish or renovate an unfinished area of the home in the future, a radon test should be taken before starting the project, and after the project is finished. Generally, it is less expensive to install a radon-reduction system before (or during) renovations rather than afterward.

a. Why should I buy a radon-resistant home?

Radon-resistant techniques work.  When installed properly and completely, these simple and inexpensive passive techniques can help to reduce radon levels.  In addition, installing them at the time of construction makes it easier to reduce radon levels further if the passive techniques don't reduce radon levels below 4 pCi/L.  Radon-resistant techniques may also help to lower moisture levels and those of other soil-gases.  Radon-resistant techniques:

In a new home, the cost to install passive radon-resistant features during construction is usually between $350 to $500.  In some areas, the cost may be as low as $100.  A qualified mitigator will charge about $300 to add a vent fan to a passive system, making it an active system and further reducing radon levels.  In an existing home, it usually costs between $800 to $2,500 to install a radon mitigation system.