Stormwater runoff is one of the leading causes of water pollution in the United States. As it flows, stormwater runoff picks up dirt, trash, oil, grease, chemicals, and other pollutants. Stormwater runoff is not treated so those pollutants are carried to waterways, canals, parks, community lakes, retention basins, and drywells. Polluted stormwater runoff can have negative impacts to aquatic ecosystems, the environment and our drinking water sources.