The District of Columbia Department of Environment & Energy: Radon
Testing your home for radon is as simple as opening a package, placing a radon detector in a designated area, and after the prescribed number of days, sealing the detector back in the package. Fixing a radon problem is usually just a matter of caulking cracks along basement foundations, sealing leaks around pipes, and taking other steps to prevent radon from entering the house through places where it is in contact with the ground.
The District of Columbia Department of Environment & Energy (D.O.E.E.) provides district residents with a free radon test kit by calling the radon hotline at (202) 535-2302 or by submitting request a free radon test kit.