Our drinking water supplies, fishing and recreational waters are fouled by uncontrolled pollution when rainwater and snowmelt wash over city streets, parking lots, and suburban lawns and pick up toxic chemicals, disease-causing organisms (from pet waste), and dirt and trash. This problem is called urban stormwater pollution. Recent studies have found that urban stormwater rivals and in some cases exceeds sewage plants and large factories as a source of damaging pollutants. Two hundred years of unregulated, unmanaged urban stormwater have contributed to many severe public health problems and expensive natural resource losses in the United States.