AWWA ACE58284

San Diego County's prosperity has always been tied to its water supply. With limited rainfall and a burgeoning population, water agencies are constantly challenged to keep the taps flowing. The wholesale operation of the San Diego County Water Authority provides water to the region, which is then delivered to customers by 25 different retail agencies through their own distribution systems of pipelines, reservoirs, pump stations, and regulating facilities. Planning these distribution systems and their component facilities has evolved with the changing San Diego environment. This paper discusses the lessons learned from 15 years of experience in the San Diego area water supply and distribution system planning. The lessons include: invest in planning; distribution system planning starts with supply; integrated facilities planning provides essential interaction of engineering and financial issues; a fire flow analysis is not always just a fire flow analysis; dynamic hydraulic models can be useful tools; criteria may vary from district to district, and that's OK; geographic information system (GIS) is the new platform for analysis and data management; water supply and system reliability issues are important; asset management is here to help (CMOM and GASB 34); and, the future will be like the past, only more so. Includes figures.