Radon can enter a home in a number of ways, including through floor joists, floor drains and sump pumps, soil tracked in from outside, cracks in the concrete, porous walls, and cracks in the chimney. Radon can even enter a home through the water supply.
Because radon comes from the soil, the lowest level of a house will likely contain the highest concentration of radon.
The EPA recommends that buyers always get a home tested for radon by a licensed radon testing specialist. While some home inspectors test a home for radon gas as part of the inspection process, this isn’t always the case, so it’s good to double check.
If the sellers conduct radon testing before listing their home, they should reveal test levels on any disclosure forms.
There are two types of radon tests: a short-term one that takes about 48 hours to complete, and a longer one that takes several months. The short-term test is the most common.
The EPA recommends radon remediation if a radon level is 4 pCi/L or higher, but notes that radon levels less than 4 pCi/L still pose a risk, and in many cases, may be reduced. If radon is found, measures such as sealing cracks in the foundation and venting air out of the home can help reduce radon levels.