Frequently Asked Questions: Radon & Radon Testing
What is radon?
Radon is a colorless, odorless, and tasteless naturally occurring, radioactive gas. It is created by the decay of uranium in the ground and is found everywhere in the U.S., most commonly in rocky soils, like granite, shales, phosphates, etc . Radon gas is not a danger in the outdoor air. The health risks associated with radon only become an issue when the gas enters and is trapped inside a building, such as a home, school or workplace, and cannot escape. Radon gas is chemically inert, which means that it will not interact with any known substance or object, allowing it to pass freely and easily through common building materials like wood, drywall, and concrete.
How can I test for radon?
The presence of radon gas is detected using either a short- or long-term radon test. Short-term tests are tests lasting 2-7 days, and long-term tests are in place for at least 90 days. Options for short-term testing include continuous radon monitors (CRMs) and activated charcoal kits. Alpha-track test kits are used to perform long-term tests.
What are the health effects of radon?
Although radon itself is a relatively harmless gas, its decay products are not. Radon can be inhaled and exhaled without harm. However, if the radon atom decays while it is inside your lungs, the radioactive atom it decays into cannot be exhaled and becomes trapped in the lungs. As this radioactive atom undergoes further decay into other radioactive atoms, they continue to destroy the surrounding lung tissues. The higher the radon level, the larger the number of these decay products, and the greater the tissue destruction. Prolonged exposure to high levels of radon gas and its decay products can lead to respiratory problems and lung cancer.
Beware of area testers and mitigators who use scare tactics to intimidate and frighten homeowners into thinking that the homeowners and their families are in immediate danger, that they are the only ones who can resolve the problem, and that it must be done as soon as possible.
What is considered a safe radon level?
Exposure to radon gas is not considered a health risk outdoors because wind and air movement reduce concentrations of the gas to very low levels. Indoors, however, as the concentration of radon gas increases, so does the health risks associated with exposure to it. The Environmental Protection Agency (EPA) has set 4.0 picoCuries of radon gas per Liter of air (4.0 pCi/L) as the Action Level: the point at which they recommend installation of a radon mitigation system.
Because radon levels in a home are not constant—and fluctuate over months, days, and evens hours—it is possible that the radon level in your home will be higher than 4.0 pCi/L on some days and lower than 4.0 pCi/L on others. Short-term weather patterns can also greatly influence this variation. Therefore, it is important to realize that the EPA Action Level of 4.0 pCi/L is meant to be your average ANNUAL exposure level, and not the results from a short-term test. A long-term alpha-track test kit left in place for one year would give the most reliable number for the average annual radon level in your home.
I have a (slab/basement/crawl space) home. Do I need to test my home?
Yes. It is a myth that only certain types of homes have issues with radon, or that homes constructed in a specific way will not have elevated radon levels. The presence or absence of radon in a home will depend upon whether or not there is uranium in the soil beneath the home, not the construction of the home itself. The only way to know the radon level inside a home is to perform a radon test. The EPA recommends that every home in America be tested, regardless of location or construction style.
Is the radon level the same everywhere in my home? Where in my home should I test?
Radon is going to be at its highest concentrations on the lowest levels of the home. In a ranch-style home, where the living space is all on one floor, the radon level would be expected to be relatively uniform throughout that type of home. However, in a home with more than one floor, the radon level decreases on upper floors because radon gas is much heavier than air and tends to concentrate in the lowest level of the home. As a general rule, the radon level on any floor is approximately half of the level on the floor below. Thus, a home with a radon level of 8.0 pCi/L in the basement would be expected to have a radon level of approximately 4.0 pCi/L on the first floor and 2.0 pCi/L on the second floor.
Because radon is at the highest levels on the lowest floor, the radon test should be performed on the lowest level. Unfinished basements are considered valid testing environments; therefore, if a home has an unfinished basement, the test should be performed there. If a basement has both a finished area and an unfinished area, the finished area should be tested. In finished areas, the test will usually be placed in a commonly occupied room such as a bedroom or family room. Kitchens, bathrooms, and closets are INVALID testing environments.
My neighbor (did/did not) have high radon levels; will my radon level be the same as my neighbor's?
Are there certain areas of the Triangle that don't need to be tested or areas with elevated radon levels?
Yes and no. Radon levels can vary from home to home, even with next door neighbors. The presence or absence of radon in one home is no indicator of radon levels in homes nearby. Although "hot spots" of radon do exist, it is possible to have several neighbors with elevated radon levels and not have an issue in your own home. It is even possible for your house to be the only one on your street block that does not have a high concentration of radon, or to be the only house on your street block that does. The only way to know the level of radon in your home is to perform a radon test.
While every home should be tested, there are areas of the Triangle where homes will have a higher average radon level than others. Homes inside the beltline often have elevated levels of radon. The granite bed that exists beneath the center of the city extends north and east, meaning homes in Wake Forest, Youngsville, Franklinton, Knightdale, and Wendell often have elevated levels of radon, as well. Parts of Durham and Chapel Hill also have rocky soil, translating to homes with increased levels of radon. We have also tested and mitigated elevated concentrations in homes in Cary, Apex, Holly Springs, Morrisville, and Fuquay Varina. High levels of radon have been found in homes throughout the entire RDU area. The only way to find out the radon level in a particular home is to test it.
What happens if my radon test indicates levels are higher than acceptable?
If you are a homeowner testing for your own information, and the first test result is between 4.0 pCi/L and 8.0 pCi/L, the EPA recommends conducting a second test, preferably a long-term test, to more accurately determine the average radon level in your home over a longer period of time (a 1-year alpha-track test is ideal). If that test result is also at or above 4.0 pCi/L, the EPA recommends mitigating the home. For the situation where the first radon test result is above 8.0 pCi/L, the EPA recommends a second-short term test be performed shortly after the first test. If the average of those two test results is greater than 4.0 pCi/L, the EPA recommends mitigation.
If the test has been conducted a part of a real estate transaction, the protocol changes because of the time-sensitive nature of the industry. In this case, the first test is usually performed on behalf of the buyer. If the result of that first test is above 4.0 pCi/L, the test appears to have been performed in accordance with applicable guidelines, and there is no reason to doubt the validity of the test result, the EPA recommends mitigation at that point. Buyers are not under any obligation to accept results of other retests performed once they have obtained a high radon reading.
Should I test my water for radon?
Before testing a home for radon in the water, a radon-in-air test should be usually be conducted first (or at the same time). If the radon-in-air test reveals low radon levels, there is generally not a need to test the water, since the water is adding little or nothing to the indoor air radon level. However, if the results of the radon-in-air test are unacceptably high, AND you have a private well on your property serving your home, then you should test the well water to see if the water is a contributor to the radon level in the air in your home. If the radon-in-water levels are low (below 10,000 pCi/L), they would not be a major contributor to the radon levels in the air, and the water would not usually need treatment.
More information on radon in water is available on our
Where can I get more information about radon?
While there is an abundance of information about radon gas and its health effects on the Internet, it is sometimes difficult to separate fact from fiction because not all of the information found there is correct, and distortions, misinformation, opinions, and falsehoods abound. The best sources for information about radon gas will be obtained from government organizations, such as the EPA and state radon offices, and certifying organizations, such as the NRPP and NRSB.
More information is also available on our