The homeowner of a house can test their home prior to listing the home for sale. If the homeowner does perform a radon test, most if not all states will require that the test result be disclosed on the whole house disclosure form you will fill out with your realtor. If the initial test by the homeowner comes back less than 4 pCi/L, potential buyers may still request an additional radon test as part of their home inspection. If an initial radon test by the homeowner is 4 pCi/L or greater, the issue will need to be addressed in the real estate transaction. A buyer may want to have a confirmatory test conducted. With an average radon level of 4 pCi/L or greater, it is recommended that a radon mitigation system be installed prior to placing the house on the market, to bring the radon level to less than 4 pCi/L.