Which part of a plumbing system collects water that may ultimately be discharged?

The plumbing system's primary component responsible for collecting water, which may eventually be discharged, is the drainage system. This system consists of pipes, fittings, and other elements designed to transport wastewater away from fixtures, such as sinks and toilets, to a treatment facility or municipal sewer.

Fixtures, while essential components in a plumbing system, serve as the outlets for water, allowing users to access and utilize water for various purposes, such as bathing or cooking. They do not inherently collect water for later discharge; rather, they are the endpoints where water is used and subsequently drained.

The drainage system plays a crucial role in managing wastewater and preventing overflow or contamination, ensuring that any collected water is safely transported away. Other options like the distribution box and storm drainage systems serve additional specific functions related to the organization and management of collected water but do not serve the primary role of directly collecting the wastewater in the same manner as the drainage system.