Radon removal can, with a good effect, be used to remove radon from well water. For installations based on aeration only the radon gas is removed, not the radon progeny. The aim of the study is to get an indication of the effect on short-lived progeny and possibly of implications for the effective dose. The short-lived radon progeny have been investigated in the raw and the cleaned water from six private wells where radon aerator systems based on aeration and recirculating of the water have been installed. The results from this pilot study indicate that the short-lived radon progeny in some cases follow the water to the tap for consumption to such an extent that the problem with the remaining short-lived progeny should be considered. The extent of the study is not sufficient for general conclusions. However, it is important to stress that the effective dose from the short-lived progeny is always lower than it would have been from the radon, when no radon removal is used.
