Before arriving at our Plum Island Wastewater Treatment Plant, wastewater travels through miles of sanitary sewer lines, a network of pipes that is separate from the storm water system.

Charleston Water System has more than 600 miles of sewer pipe, including gravity and pressurized force mains. Because of Charleston's flat topography, Charleston Water has a large number of pump stations (about 185), which are necessary to pump wastewater to the plant.

Charleston Water also has about 16 miles of deep tunnels, which collect wastewater from shallow sewer pipes and carry it to the plant for treatment. Since 1998, Charleston Water has been replacing these tunnels in a massive, phased project. Learn more about the Sewer Tunnel Replacement Project.

The Wastewater Collection Department is responsible for operating and maintaining the sewer system, including cleaning manholes, conducting smoke and dye testing to reduce infiltration and inflow, and other corrective and preventative maintenance activities.

In 2009, our Wastewater Collection Department received a National Environmental Achievement Award from the National Association of Clean Water Agencies for it's Infiltration/Inflow Reduction Program. This project eliminated sources of rainwater in the sewer system, which takes up needed capacity and can cause sewer overflows during heavy rainfall.