Radon is a cancer-causing, radioactive gas. You cannot see, smell or taste and has been found in homes all over the United States. It comes from the natural breakdown of uranium in soil, rock and water, and gets into the air you breathe. Radon typically moves up through the ground to the air above, and into your home through cracks and other holes in the foundation. Radon can also enter your home through well water. Your home can trap radon inside.