What is the Combined Sewer Overflow (CSO) issue?
The CSO issue is the overflow of untreated sewage that is discharged to the harbor when a storm event causes more sewage flow to the treatment plant than the plant can hold or treat. This is a result of the storm sewers and the sanitary sewers being combined, meaning that the storm sewers in some areas of the city flow to the sewage treatment plant. When major storm event occurs, the plant overflows, and the outflow is disinfected but not treated to required standards.
