The stormwater drainage system is a route of drainage for precipitation (rain or snow). Once the precipitation hits the ground and starts to flow over land it is called runoff. Runoff can carry with it materials from highways, streets, and gutters into the stormwater drainage system. This runoff can carry harmful materials (such as gas, oil, pet waste, fertilizers and pesticides) to streams, ponds, and rivers making them unsafe for drinking, fishing, swimming, and other activities. Prevention of contaminated runoff is a growing concern across the nation.