Should I test the soil for radon before building?

Soil testing for radon is not recommended for determining whether a house should be built radon-resistant. Although soil testing can be done, it cannot rule out the possibility that radon could be a problem in the house you build on a lot. Even if soil testing reveals low levels of radon gas in the soil, the amount of radon that may enter the finished house cannot be accurately predicted because one cannot predict the impact that the site preparation will have on introducing new radon pathways or the extent to which a vacuum will be produced by the house.  Furthermore, the cost of a single soil test for radon ranges from $70 to $150, and at least 4 to 8 tests could be required to accurately characterize the radon in the soil at a single building site.  Therefore, the cost to perform the soil testing is very high when compared with installing the passive radon system in high radon potential areas (see the EPA Map of Radon Zones at www.epa.gov/radon/zonemap.html).