Storm water runoff occurs when rainfall flows over the ground. Impervious surfaces like parking lots, rooftops and streets prevent storm water from naturally soaking into the ground. More impervious surfaces means more storm water runoff entering the County’s storm drain system which includes curb inlets, underground pipes, road side ditches, creeks, streams, and rivers.

Non-point source pollution is caused from pollutants of varying origins and occurs when storm water runoff picks up and carries debris, chemicals, dirt and other pollutants into our storm drain system. Anything that enters our storm drain system is discharged untreated into the water bodies we use for swimming, fishing, recreation and drinking water.

Some common pollutants found in storm drains and creeks include: motor oil, yard clippings, fertilizers, pesticides, milky water from paint, soapy water from car washing, eroded sediment and concrete by-products from construction projects and litter. Because all runoff cannot be captured and treated like sewage, the best prospect for cleaner water is to prevent runoff from becoming polluted in the first place.