Radon in Water
The radon in your home's indoor air can come from two sources: the soil and your water supply. Compared to radon entering your home through water, radon entering your home through soil is a much larger risk. If you've tested for radon in air and have elevated radon levels, and your water comes from a private well, have your water tested. The devices and procedures for testing your home's water supply are different from those used for measuring radon in air.
The radon in your water supply poses an inhalation risk and an ingestion risk. Research has shown that your risk of lung cancer from breathing radon in the air is much larger than your risk of stomach cancer from swallowing water with radon in it. Most of your risk from radon in water comes from radon released into the air when water is used for showering and other household purposes.
Radon in your home's water is not usually a problem when its source is surface water. Radon in water is more likely when its source is ground water, e.g., a private well or a public water supply system that uses ground water. Some public water systems treat their water to reduce radon levels before it is delivered to your home. If you are concerned that radon may be entering your home through the water, and your water comes from a public water supply, contact your water supplier.
If you've tested your private well and have radon in your water supply, it can be treated in one of two ways. Point-of-entry treatment can effectively remove radon from the water before it enters your home. Point-of-entry treatment usually employs either granular activated-carbon (GAC) filters, or aeration devices. While GAC filters usually cost less than aeration devices, filters can collect radioactivity and may require a special method of disposal. Point-of-use treatment devices remove radon from your water at the tap, but only treat a small portion of the water you use, e.g., the water you drink. Point-of-use devices are not effective in reducing the risk of breathing radon released into the air from all water used in the home.
