A radon map is a map of a given area which charts information about radon levels. Radon maps are often created and maintained by government agencies concerned with environmental safety, although they can also be maintained by private organizations. There are a number of uses for radon maps which make them valuable tools. They are usually freely available by request, and members of the public can ask local government officials for their own copies of a regional radon map.
Agencies which maintain such maps stress that the maps are not designed to be used in lieu of radon testing. The maps are also not supposed to be a guideline for testing; radon can appear in structures anywhere, regardless as to where they are on a radon map. Radon maps also cannot be used in real estate transactions, as they do not provide information about specific properties. A real estate agent cannot, for example, state that a home is in a low zone with the goal of making buyers believe that the home is radon free.
A typical radon map takes known values and plots them. The values are divided into low, medium, and high zones. Many things can influence radon levels, and being in a high zone on a radon map does not necessarily mean that other environmental hazards are also present. Conversely, being in a low zone doesn't mean that an area is free of contamination, or that structures within the low zone are likely to be low in radon.
Primarily, radon maps are used when developing building codes which are designed to improve building safety. The idea is that in a high zone, it may be a good idea to include stringent precautions in the building code to reduce the risk of radon buildup. Such precautions can include the installment of systems used to manage radon buildup in structures, as well as the use of radon-resistant construction techniques which are intended to prevent radon from entering a structure.
A radon test can be easily performed with a kit which is mailed back after radon sampling. The costs of such tests vary, and in some cases, people can obtain free test kits and low cost testing. Radon testing is the only way to determine how much radon is present in a structure, and is recommended before real estate transactions and before major renovations, as the test results may play a role in planning renovations and property purchases.