- Courtesy City of Colorado Springs
A permitting mechanism is designed to prevent runoff from washing harmful pollutants into local surface waters and, ultimately, waters of the United States.
Stormwater runoff from rain and snowmelt flows over land or impervious surfaces, such as paved streets, parking lots and building rooftops, and wherever it cannot soak into the ground. The runoff picks up pollutants like trash, chemicals, oils, and dirt/sediment that can harm rivers, streams, lakes and coastal waters.
To protect those resources, communities, construction companies, industries and others must use stormwater controls, known as best management practices.
MS4 permits require cities to develop management programs consistent with requirements of the Clean Water Act and other environmental laws.