Radon Levels in Water

Radon, an odorless and colorless gas with radioactive properties, has received high levels of attention as an air contaminant. The U.S. Environmental Protection Agency recommends testing of every home and correction of any problems that are found because airborne radon can cause lung cancer. But radon can also cause adverse effects by infiltrating your water.

Risk

Each year in the United States, between 30 and 1,800 people die because of radon in their household water, the U.S. Centers for Disease Control and Prevention. Homes at risk are those that depend on a well for their water or whose public water system uses groundwater. Radon levels can run high in the groundwater of some areas where the water flows against granite, granitic sand or formations of gravel. Drinking the water could increase your risk of stomach cancer. Water from radon can also become airborne when the water is disturbed through washing dishes, showering or other activities.

Levels

For every 20,000 to 40,000 picocuries per liter (pCi/L) of radon in your water, there is an additional 1 percent to 2 percent chance of dying from cancer, according to the University of Maine. That is the same level of added mortality risk that you would get with just 4 pCi/L of airborne radon, which causes lung cancer. The U.S. Environmental Protection Agency has proposed regulations forbidding local water systems from supplying water with more than 4,000 pCi/L.

Solutions

Two methods are available for removing radon from your water. Aeration treatment involves either spraying the water or mixing it with air and then venting the air from the water. Another treatment is called GAC, for granular activated carbon. You filter water through and the radon sticks to the carbon, according to the CDC. Whichever option you choose, you should install it to treat water at the point of entry, so that all of the water coming into your house will be radon free. Devices at the point of use, such as under a tap or under the sink--treat only a small portion of your water and are not very effective, according to the CDC.

Costs

Testing for radon in your water typically costs between $25 and $50, according to Pennsylvania's Bureau of Radiation Protection. You can obtain such testing by getting in touch with your public water supplier or your state's radon office. If you have a water radon problem and fix it with aeration, you can, as of 2010, expect to pay between $3,000 and $4,000. GAC treatment costs between $1,000 and $1,500.

Perspective

Researchers have not found "direct and conclusive evidence" to link home radon exposure--either via water or air--to a higher incidence of cancer, according to the University of Maine. Current models of risk rely on extrapolations from populations who were exposed to high radiation levels, such as uranium miners. At the lower levels that average people might be exposed to, scientists have to make some assumption. "The uncertainties are so great," the University of Maine notes, "that the actual risks might (be) double--or half--the estimated risks."