Wastewater vs. Stormwater

Charleston Water System’s sewer system collects wastewater only, not stormwater, which is handled by a separate collection system.
Wastewater Sink Drain
Stormwater Street Grate
Wastewater, or sewage, comes from drains and toilets in homes and businesses. It's treated at a wastewater treatment plant before being released back into a waterway.
Stormwater is rain water that does not soak into the ground. It flows over roads and parking lots and into storm water drains, which empty directly into waterways. Stormwater is not treated.

Managing Wastewater & Storm Water


In the city of Charleston, storm water is managed by the City's Department of Public Service. We act as a billing agent for collection of the City’s storm water fee, so the fee appears on our water bills, but the fee is not determined by Charleston Water System and all revenue goes to the City, minus a nominal processing fee that we retain.

In fact, we regularly smoke test our wastewater collection/sewer system to keep groundwater and storm water out. Water that enters the system through cracked pipes, damaged manholes, improper storm drainage connections, etc. is called infiltration and inflow, or I&I. I&I increases treatment costs and consumes hydraulic capacity in sewer mains, pump stations, and can cause sewer overflows during periods of heavy rain.

If you have a storm water/drainage issue, contact your town, city, or county.