What does the term “drainage grade” refer to?

The term “drainage grade” specifically refers to the required slope for drainage lines. This slope is crucial as it ensures that wastewater flows efficiently through the drainage system by utilizing gravity. Proper drainage grade helps prevent issues such as stagnant water, which can lead to blockages and unpleasant odors.

In plumbing design, maintaining the correct drainage grade is essential for effective drainage system performance. The typical recommended slope is often around 1-2% (1/8" to 1/4" per foot) for sewage and other wastewater lines. This ensures that the water moves freely and does not cause pooling or backflow, which could lead to system failure. The importance of the drainage grade lies in its fundamental role in the overall functionality of plumbing systems.