Most municipal storm water programs in southern California focus on the protection of water quality and beneficial uses of urban creeks and ocean beaches. With recent beach closures impacting water contact recreation and the local business that depends on it, significant resources have been spent studying and solving this problem. Consequently, municipal storm water permits and the compliance programs to support them have tended to focus on BMPs that address downstream uses of these receiving waters, such as controls for coliform bacteria and heavy metals. But what happens when the receiving water is a drinking water reservoir? Since reservoir operators are driven by the need to provide safe, appealing drinking water, the pollutants of concern for these systems – and the BMPs to address them – are different than those for the protection of downstream coastal uses. To address this concern, the San Diego Water Department (SWWD) has undertaken a project to develop source water protection guidelines for storm water runoff draining into its nine raw drinking water reservoirs (Figure 1).