Video narration
Where does rain go when it slips into a street drain? After a shower, water runs along the gutter, gathering from pavement until it reaches that opening. That water is stormwater: rain flowing over streets and other hard surfaces. At the drain, an inlet lets it leave the street and enter pipes beneath your feet. Those pipes carry it onward, away from the curb. The water hasn't vanished. The drain is only the entrance to a route. Depending on the system, that route can lead to an outlet, where water is released, or a storage area, where it is held; some systems treat water before release. So a street drain doesn't send every drop to the same place. Rain from your gutter travels through the drain and pipes to an outlet, storage area, or treatment site; the system determines where it ends.