What is stormwater?
Impervious surfaces, such as rooftops, driveways, sidewalks, and roads prevent rainwater from soaking into the ground. When it rains on these hard surfaces rainwater becomes stormwater runoff, which picks up pollutants that have been left on the ground--such as pet waste, excess fertilizers, litter, oil, and gasoline--and sweeps them downstream. Some of this runoff may flow directly across the land into a nearby waterway, while some may enter a ditch or storm drain and follow an underground path that eventually discharges to a waterway. Either way, stormwater is untreated, so all of the pollution we leave on land can ultimately end up in the water downstream. As a result, stormwater runoff is considered the greatest threat to water quality in the United States. In South Carolina more than 1,150 of our waterways have been classified as "impaired," which means they are too polluted or degraded to meet accepted water quality standards. Because we all contribute to stormwater pollution, it is up to all of us to take action to protect water quality.Stormwater 101