Stormwater is rainwater or snowmelt that isn't absorbed into the ground. Stormwater runs off rooftops, down street curbs, and across parking lots where it enters the storm drains.
Storm drains are often confused with sanitary sewers, but in the City of Charlotte and Mecklenburg County, they are separate systems and very different. Storm drains take rainwater through underground pipes directly into a local stream or lake. Stormwater is not cleaned at a treatment plant.
Sanitary sewers carry sewage from our homes to a wastewater treatment plant to be cleaned before it is released into a stream, river, or lake. Examples of sewage include dirty water from our toilets, showers, kitchens, and laundry machines.
Because stormwater is not cleaned at a treatment plant, the storm drainage system can carry pollution from our yards and streets directly into local streams, rivers, and lakes.
Stormwater, Wastewater and Drinking Water graphic to visualize these three water systems.
If you want to see photos and learn the names of common stormwater infrastructure found around homes, streets, and businesses, please see
Storm Water Services Photobook.
Pollution of Streams and Lakes
Stormwater is the number one pollution problem for our nation's streams and lakes. Rainwater washes off a variety of pollutants from the land into the storm drainage system and into streams, rivers, and lakes.
Nonpoint source pollution is another name for stormwater pollution. Nonpoint source pollution comes from all over the land. Here are some common examples of nonpoint source pollution:
Soil from construction sites
Oil from cars
Fertilizers and pesticides from yards
Dog poop from parks and yards
Litter from streets
Point source pollution is another problem for our streams and lakes. Point source pollution comes from a single source. Common examples include:
Sewage overflows from a sanitary sewer
Dumping of wastes from a business or person
Spills from auto accidents
Another problem for streams, rivers, and lakes is the volume of stormwater generated in the urban environment. As a community becomes more urban, there are more impervious surfaces. Impervious surfaces don't allow rain to be absorbed into the ground generating a lot more stormwater. Examples of impervious surfaces include sidewalks, roads, and rooftops.
All that stormwater rushes directly to a stream and acts like a fire hose, eroding stream banks and filling the stream with a lot of sediment or mud. The velocity of stormwater during a storm combined with all the sediment or mud generated makes it difficult for aquatic organisms, like fish, to live.
Consider this example:
one inch of rain on an acre of woods
produces little to no stormwater runoff.
one inch of rain on an acre of asphalt
produces 27,000 gallons of stormwater runoff
that contains a variety of pollutants
and causes widespread erosion.
Detention basins and stormwater regulations associated with land development activities help manage volumes of stormwater. Detention basins help slow down stormwater so it can be slowly released to a local stream and pollutants, like sediment, can settle out.
Here is a great video from KeepingWatch.org that talks about the problem of stormwater in our local creeks:
Almost Worthless if Polluted Video
Here are some links to learn more about the quality of our local streams and lakes:
What Can I do to Help Prevent Pollution?
Prevent Pollution. See our
Top Ten Tips for preventing pollution.
Report Pollution. If you see a discolored stream, or if it smells strange, report it. When in doubt, report it. See
Report a Problem to learn about three ways to report pollution.
Educate. According to public opinion survey, approximately 50% of City and County residents don't know storm drains lead to streams and lakes. Help inform people that storm drains go directly to streams and lakes.
Help teach kids and students about stormwater and environmental stewardship through one of our many