Frequently asked questions about radium in drinking water
Wisconsin Department of Natural Resources
Some Wisconsin community water supplies have naturally-occurring radium in quantities that exceed the safe drinking water standard. This Web page will answer common questions about how and where radium occurs in water supplies; what are its health effects; options communities and private well owners have to remedy this problem; and radium regulations.

Radon and Your Home
by James R. Brooks March, 1988
Radon, first discovered in 1910, is a colorless, odorless, radioactive gas formed from the radioactive decay of radium. Radium in turn is formed from uranium which is present to some extent in all rocks but is most common in those of granitic composition. It is not unusual for granites to contain as much as 3.9 parts per million uranium and .0013 parts per billion radium. When rocks weather, these radioactive elements find their way into the soil. Radon has a half-life of only 3.8 days; consequently, most of the gas decays harmlessly in the ground or atmosphere.

The primary source of radon in homes is from the underlying soil and bedrock. However, an additional source could be the water supply, particularly if the house is served by a private well or a small community water system.