Radon is a radioactive gas you can't see, taste or smell. It's found throughout the United States and can move up through the ground and into a home through cracks and holes in the foundation. Compared to radon entering the home through soil, radon entering the home through tap water will in most cases be a small source of radon in indoor air.
Radon is a known human carcinogen. Breathing air containing radon can lead to lung cancer. Drinking water containing radon also may cause increased risk of stomach cancer.
If you're concerned about radon in your home, test the air in your home. Testing is inexpensive and easy. Fix your home if the level of radon in your air is 4 picocuries per liter of air (pCi/L) or higher. For more information, call the Radon Hotline at (800) S0S-RADON.