MY NEIGHBOR TESTED: NO RADON. DO I NEED TO TEST? Wish we could tell you to relax, but.... Radon gas is very site specific. Readings can change within a couple feet. We once tested the basements of a duplex and found different levels in each unit. Maybe there was a bigger deposit of uranium under one, or maybe nearby gas leached more into that unit. Our advice: Test your property. Don't rely on a neighbor's report. Don't rely on an old Radon Test.