Green Streets are streets that have been transformed from "water conveyance channels" designed to route rainwater unfiltered swiftly into the Los Angeles River and other tributaries to streets where rainwater is intercepted and cleaned using "nature's services" provided by soil and vegetation.

To do this requires retrofitting driveways, sidewalks, parkways and streets with devices to intercept the water and direct it into places where it can percolate through gravel and soil and be taken up by plant roots into the plants themselves.

Both of these methods act as filters to remove debris, sediment, grease and oil, trace metals and bacteria from the water. These methodologies provide the added benefit of safely storing this stormwater naturally underground within the local sub-watershed, and transpiring it back into the atmosphere.