How climate change could cause more sewage overflows

As it meandered across South Carolina’s Lowcountry in August 2024, Tropical Storm Debby left a wake of sewage in its path. The storm’s heavy rainfall spurred dozens of sanitary sewer overflows across the state.

In a warming world, South Carolina could experience many more storms like Debby — drenching rain events that provoke troublesome and dangerous sewage spills.

These overflows occur when stormwater infiltrates a sanitary sewage line, causing the system to become over-burdened and blow back untreated or partially treated sewage. That sewage then washes into the state’s rivers, streams or lakes where it can create hazardous swimming and fishing conditions.

These kinds of overflows are common. The S.C. Department of Environmental Services estimates that the state experiences about 60