There are 21 municipalities in New Jersey with a combined sewer system (CSS), where stormwater runoff, human waste and industrial wastewater run through the same pipe. The system overflows when the lines exceed capacity during heavy rainfalls or snowmelts—discharging untreated wastewater directly into rivers and even backing up into streets, flooding people’s homes—although, in many cities, such as Paterson, it doesn’t take much rain to overwhelm the system.
As a result, combined sewer overflow (CSO) systems are a priority water pollution concern across the United States, subject to the National Pollutant Discharge Elimination System (NPDES) permitting program.
