What defines a combined sewer system?

A combined sewer system is characterized by its ability to handle both sewage and stormwater runoff within the same pipeline. This design facilitates the collection of wastewater from homes and businesses, as well as rainwater and melted snow, all integrated into one system. Such systems are common in older urban areas where separate sewer systems were not implemented. This dual functionality can lead to challenges, particularly during heavy rainfall when the system may become overwhelmed, resulting in combined sewer overflows that can discharge untreated waste into nearby waterways.

The focus on the design of a combined sewer system highlights its operational efficiency for communities that have not transitioned to separate sewer systems. Understanding this definition is crucial for studying urban water management and planning strategies to mitigate overflow problems.