What is the term used to describe the slope of drainage pipes to facilitate flow?

The term that describes the slope of drainage pipes to facilitate flow is "pitch." Proper pitch is crucial in plumbing systems because it allows wastewater to flow efficiently through the pipes by using gravity. A correct pitch ensures that there are no low points where water can collect, which could lead to clogs and backups. In plumbing, a common standard for the pitch in drainage pipes is typically ¼ inch per foot for pipes 3 inches in diameter or smaller and ⅛ inch per foot for larger pipes.

Other terms like "rise," "drop," or "angle" do not accurately define the specific requirement for drainage pipe slope. "Rise" generally refers to an upward movement or elevation change, while "drop" implies a downward decrease but lacks the context of slope for drainage. "Angle" refers to the degree of inclination but is not specifically tied to the requirement of drainage systems. Thus, "pitch" is the appropriate and technical term used in plumbing to describe this essential characteristic of drainage pipes.