What does 'indirect waste' refer to in plumbing?

Indirect waste refers to a method of discharging wastewater in which the wastewater is not directly connected to the drainage system. Instead, it is discharged through an intermediary means, such as a drain fitting that allows it to flow into a receptor, like a floor sink or a trap, without creating a direct pathway to the sewer system. This approach is designed to prevent potential backflow and contamination of potable water systems, ensuring that wastewater is handled safely and complies with health and safety regulations.

The other options, while related to plumbing concepts, do not accurately describe indirect waste. A direct connection to the drainage system involves a direct discharge of wastewater, which does not qualify as indirect. Venting systems pertain to how waste and air move through plumbing fixtures and systems, rather than how wastewater is discharged. Graywater recycling deals with the reuse of non-potable water from baths, sinks, and washing machines, which is a separate topic from the concept of indirect waste.