Wheeler & Gray designed multiple prototype storage structures for hazardous waste accumulation sites at various facilities throughout California for Southern California Edison. The storage structures were designed for future compliance with the new Draft Industrial General Permit for Storm Water Discharges issued by the State of California. The structures will provide compliance elements with site and municipal Water Quality Management Plans and the Municipal General Permit for storm water discharges. The eleven designs were completed for service centers and substations and will be used as prototypes for other SCE properties. Each of the structures was adapted to the site topography at each facility. The layout of each structure was adapted to the particular operational requirements at each facility. The structures were designed to contain spills from various type of containers, such as barrels, transformer cases, switches, paints and oils. The structure also protected the stored materials from rain. Sumps and collection areas were not connected to storm drains or sanitary sewers and required pumping for removal of spilled substances.