Why Are CSOs a Concern?

CSOs contain stormwater and untreated wastewater and can potentially carry pathogens, solids, debris, and toxic pollutants to receiving waters. This may impact public health and the environment. This is a major water pollution concern for cities with CSOs. CSOs are among the primary sources responsible for beach closings, shellfish bed closures, contamination of drinking water supplies, and other environmental and public health problems.