Radon in Water
There are currently no Federal or State drinking water
standards for radon in California. Check with your water service provider
for more information on your drinking water quality. The following
is an excerpt from US EPA's Consumer's Guide to Radon
Reduction:
Most often, the radon in your home's indoor air can come from two
sources, the soil or your water supply. Compared to radon entering your home
through water, radon entering your home through soil is usually a much larger
risk. If you are concerned about radon and you have a private well, consider
testing for radon in both air and water. By testing for radon in both air and
water, the results could enable you to more completely assess the radon
mitigation option(s) best suited to your situation. 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 a
small ingestion risk. 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. Research has shown that your risk of lung cancer from breathing radon
in air is much larger than your risk of stomach cancer from swallowing water
with radon on it.
Radon in your home's water is not usually a problem when its
source is surface water. A radon in water problem 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 a radon in water
problem, it can be easily fixed. Your home's water supply can be treated in one
of two ways. Point-of-entry treatment for the whole house can effectively
remove radon from the water before it enters your home's water distribution
system. Point-of-entry treatment usually employs either granular activated
carbon (GAC) filters or aeration systems. While GAC filters usually cost less
than aeration systems, filters can collect radioactivity and may require a
special method of disposal. Both GAC filters and aeration systems have
advantages and disadvantages that should be discussed with your state radon
office or a water treatment professional. 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 from breathing radon released into the air from all water used
in the home.
For information on radon in water, testing and treatment,
and radon in drinking water standards, or for general help, call EPA's Drinking
Water Hotline at (800) 426-4791 or visit the EPA's Radon and Drinking Water Webpage.