Stormwater Pollution Outweighs Sewer Overflows, Threatening Public Health in Milwaukee.
Urban runoff, not sewer overflows, is the main source of water pollution in the greater Milwaukee area. A study compared pollutant levels in stormwater and sewer overflows, finding that stormwater had higher concentrations of pollutants. This suggests that stormwater runoff events are more frequent and contribute more pollutants to local waterways.