The Radon Map of CT only begins to tell the story of the prevalence of radon in the state of Connecticut. CT Basement Systems Radon Inc. has been in the radon mitigation and radon testing business since since 1987. Through the years, we have seen many homes test "high" for radon in zones or counties where the radon "potential" was thought to be lower. Conversely, we have have tested many homes that resulted in radon levels below 4.0 pCi/l in areas designated as having a higher radon potential.
While the Radon Map of CT may be useful as an introductory tool for radon risk assessment, it should not be the only benchmark utilized in determining whether or not a home has a radon problem. Radon is a very "site specific" danger. We have seen streets in neighborhoods where 9 out of 10 homes have elevated indoor radon in air levels. We have also seen neighborhoods where only one or two homes out of 20 have elevated airborne radon levels. Much the same can be said for radon in water levels. A neighborhood of homes with private water wells can have a wide range of waterborne radon levels even though the wells are within close proximity to one another.
Variation in airborne radon levels is not something limited to only larger tracts of real estate. I have personally tested homes that have shown variations of up to 100 pCi/l from one end of the home to the other at the very same time of testing. We attribute these variations to differences in soil composition that the home is built. Radon (and radium) are part of the Uranium 238 decay chain. It is possible to have a structure with a sufficient enough of a footprint, to cover a piece of real estate that has a significant variable in its' radium content; thereby resulting in appreciable differences in airborne radon concentrations.
The topography of a given piece of land is not a good indicator of the "radon potential" for the structure to be built on it. Ledge and rock are not reliable barometers for scoping out potential radon problem areas. I have tested plenty of homes with exposed ledge outcroppings within the structure...and have had numerous test results yielding radon concentrations <4.0 pCi/l. As a company, we mitigated a home in Glastonbury CT, with indoor airborne radon levels of 900 pCi/l...yet Glastonbury is located in a "low radon potential" area on the Radon Map of CT. The only way to know is test your home! Don't forget - if your home has a private water well...test the water for radon also!
