What is the primary function of a building drain?

The primary function of a building drain is to convey discharge from plumbing. Building drains are integral to a plumbing system, designed to transport wastewater from sinks, toilets, tubs, and other fixtures to a sewage system or treatment facility. This ensures that waste is properly removed from the building, preventing issues such as backups and health hazards.

Conveying discharge efficiently is critical for maintaining sanitation and preventing water stagnation within the plumbing system. The proper design and installation of building drains according to plumbing codes, including Kentucky's, help ensure that these systems function effectively and meet health and safety standards. The other options either do not relate directly to the plumbing system's main function or represent different aspects of building systems that are not pertinent to the primary role of building drains.