In plumbing, what is the term for the part of the drainage system that carries sewage away from a building?

The term for the part of the drainage system that carries sewage away from a building is known as the building drain. The building drain is a critical component of the plumbing system, as it collects wastewater from various fixtures within the building and transports it to the sewer or septic system. It typically includes both the horizontal run of pipe that connects to the building's fixtures and the vertical stack leading to the sewer connection.

In contrast, vent pipes are used to prevent the vacuum that could occur in the drainage system and to ensure proper air flow, while sewer laterals are the sewer lines that connect a building's drainage system to the municipal sewer system or the septic tank. Catch basins are designed to collect stormwater and prevent debris from entering the drainage system, but they do not carry sewage away from a building. Thus, the building drain specifically refers to the component that directly handles the evacuation of sewage from the premises.