Most of San Francisco is served by a combined storm sewer system, where stormwater, along with residential and commercial sewage, is directed to treatment plants prior to being released to the San Francisco Bay or Pacific Ocean. There are, however, some areas in San Francisco that are served by a separate storm sewer. In these areas, stormwater that goes into street storm drains flows directly to receiving water bodies, such as the Bay, Ocean or local lakes. We have developed a Stormwater Management Plan (SWMP) to manage stormwater in those areas of the City that are served by separate storm and sewer collection systems.
The SWMP describes specific programs that we will implement to minimize stormwater pollution in these areas, which account for about 10% of the City. In the future, other areas that have separate storm and sewer systems, such as Mission Bay-South and Treasure Island, may also fall under this Plan, should the City and County of San Francisco assume jurisdiction over them.