Storm drain systems help prevent flooding by diverting rainwater off the streets and other paved surfaces and into a natural body of water, such as a stream or ocean.
Storm drains are meant for rainwater only. Unlike the City sewer system, the storm drain system does not include a treatment or cleaning component. Consequently, anything that’s hosed down a driveway, poured down a gutter, or dumped into a culvert goes untreated through the system — eventually poisoning the wildlife and plants in our creeks, streams, and the Bay.