General Radon Information

Idaho specific radon and radon level information can be found throughout this site. You will be able to find information about certified radon inspectors in Idaho, as well as detailed radon level information for every county in Idaho.

Radon is an invisible, radioactive gas created from natural deposits of uranium and radium in the soil. Uranium breaks down to radium, which in turn decays into radon gas. Radon is an inert gas, which means it does not react or combine with the elements in the ground. Because of this, radon can move up through the soil into the atmosphere, where radon is easily diluted and presents little concern. However, when radon enters a building from the soil below, it can accumulate and become a health concern.

Radon can move up through the ground and enter buildings through cracks and holes in the foundation. Radon levels are generally highest in basements and groundfloor rooms that are in contact with soil. Factors such as design, construction, and ventilation of the home can affect the pathways and forces that draw radon indoors. According to a national residential radon survey completed in 1991, the average indoor radon level in the United States is 1.3 picocuries per liter (pCi/L). The average outdoor level is about 0.4 pCi/L. However, not all houses or buildings--even those in the same area or the same neighborhood--have the same radon level. The only way to know if you have a radon in your home is to test for it. Tests should be performed in the lowest lived-in area of the house and should be approved by National Environmental Health Association (NEHA). For information on testing companies in your area or locations where you can purchase a test kit, contact the Idaho Radon Hotline at (800) - 445 - 8647 or visit our website at www.healthy.idaho.gov under the Environmental Health section.

Several studies have been done to determine radon levels in Idaho and different results have been found each time. In 1985 and 1986, state and local health officials screened 1,018 homes for radon. Approximately one-third of the homes had high levels of radon. In 1989 and 1990, Idaho and EPA conducted a joint survey intended to be more representative of the entire state. A two-day charcoal canister test was used by 1,142 homeowners. The results, received in January 1992, indicated that more than 20 percent of the homes in Idaho had high levels of radon. Since 1990, the state radon project has been tracking the number of tests reported in Idaho. As of August 2005, 6,668 homes have reported results to the project with 37% of the homes testing high for radon. It is difficult to predict which homes may have high radon levels. Homes built side by side, on the same soil or rock, or with similar designs, can have very different radon levels. Therefore, it is recommended that all homes be tested.

No level of radon is considered absolutely safe, radon levels in a home should be reduced as much as possible. The amount of radon in the air is measured in picoCuries per Liter of air, or pCi/L. The EPA recommends fixing your home if the results of one long-term test or the average of two short-term tests taken in the lowest lived-in area of the home show radon levels of 4 pCi/L or higher. The higher the radon level, the more quickly you should have your home fixed. If a test indicates an elevated level of radon, reducing the level is usually easy and inexpensive. Sometimes homeowners can do the work themselves, although it is recommended that they seek professional guidance or have the work done by a professional, EPA-certified radon mitigator. However, if you want to do the work yourself, please call the Radon Hotline number to obtain a technical assistance document. There are several methods a contractor can use to lower radon levels in your home. Some techniques prevent radon from entering your home, while others reduce radon levels after it has entered the home. EPA generally recommends methods that prevent radon entry. These systems use a pipe to remove radon gas from below the concrete floor and the foundation before it can enter the home. If you live in an area with high radon levels and are building a new home, you should consider installing radon-resistant construction features. It is more cost-effective to include these features while building a home, rather than fixing an existing home.