The purpose of this study was to determine if evidence of radon formation exists in water distribution systems exposed to radium bearing water. The significance of radium bearing deposits in an actual distribution system depends on a number of factors, including radium content of the pipe deposit, the amount and distribution of pipe deposits, the type of deposits, and the time in which a given water volume is in contact with deposits. The study concludes that radon produced in radium-bearing deposits in the distribution system may cause radon to significantly increase in concentration. Even though the source of the deposit within a distribution system may be small in comparison to a geological source and impact only a very small fraction of the population, the importance must be gauged by the proposed maximum contamination level (MCL) of 300 pCi/L. Radon production within the distribution system may cause radon content to exceed the MCL for some users, even if compliance of the point of entry is achieved. The linkage between radium deposition and radon release may need to be considered in the final EPA radionuclide regulations.