Rain gardens are a relatively low-cost, effective, and beautiful way to reduce the amount of stormwater that runs off your property. Rain gardens capture and treat rainwater that runs off impervious surfaces like driveways and roofs. Runoff is directed towards a depression in the ground, which is planted with drought-resistant (and typically native) plants.
Rain gardens keep roof runoff from reaching the storm drain. When water flows from our roofs during storms, it runs off into storm drain inlets (or curb openings). During large storms, the storm drain system carries this polluted water to our local creeks and the San Francisco Bay.
Rain Gardens can also provide attractive habitat for birds, butterflies, and other animals, especially when planted with native plants (Source: BASMAA 2012(PDF, 798KB) ).