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. Many public water supplies use surface water which tends to have lower radon levels. If you are concerned about the public water supply, call your public water supplier.
Aeration involves spraying the water or mixing it with air and then venting the radon.
Granular activated charcoal systems filter the water through a charcoal bed. The radon attaches to the charcoal and the water leaves the charcoal tank relatively free of radon. The charcoal may present disposal problems when the charcoal bed needs to be replaced. In both of these treatment methods, it is important to treat the water where it enters the home. Trying to treat the water at the kitchen sink, for instance, would not be effective in reducing the amount of radon that enters the home.