Most drinking water utilities would agree that watershed source water protectionis the first step toward a multiple barrier approach to treatment of surface water sources. A watershed program in Utah, initiated in 1980 to protect water quality and beneficialuses in a reservoir, continues to evolve into a total watershed source protection plan to meet the challenges of both the Clean Water Act and the Safe Drinking Water Act. The purpose of this paper is to demonstrate how cooperative efforts of an aggressive water quality protection and improvement program initiated by the Clean Water Act has provided immeasurable benefits to drinking water agencies now facing the requirement of source water protection as required in the 1996 amendments to the Safe Drinking Water Act. Includes figures.