Stormwater runoff includes rain, and water runoff from your lawns, rooftops, sidewalks, roadways, and other impervious surfaces. Stormwater runoff flows through our stormwater system of drains, pipes, and ditches – in some cases untreated - into our streams, rivers, and lakes. Stormwater carries with it pollution such as oil, chemicals, fertilizers, and other pollutants it collects along the way.