What is the definition of a waste pipe in plumbing?

The definition of a waste pipe refers specifically to its function in plumbing systems. A waste pipe is designed to carry the discharge from various plumbing fixtures, such as sinks, toilets, and showers, directly to the house drain or sewer system. This discharge typically includes wastewater, which may contain organic matter, chemicals, and other substances that need to be properly transported away from the fixtures to prevent contamination and ensure effective drainage.

The other options reflect misunderstandings of the waste pipe's role. A pipe that only carries clean water pertains more to supply lines rather than waste, while a pipe that conveys special waste would not encompass the general functionality of waste pipes, which handle all kinds of domestic wastewater. Finally, a pipe that connects only to outdoor drainage would imply a specific use-case scenario rather than the broader definition of what a waste pipe entails within the plumbing system. Thus, the correct understanding aligns with the role of a waste pipe in efficiently managing wastewater from household fixtures.