What is the minimum slope recommended for a drainage pipe smaller than 2 inches?

The minimum slope recommended for drainage pipes smaller than 2 inches is commonly set at 1/4 inch per foot. This specific slope is crucial because it ensures adequate flow of wastewater through the pipe, preventing issues such as blockages and backups. A slope that is too shallow might not provide enough gravitational force to move the waste effectively, potentially leading to stagnation where solids can settle and form clogs.

By establishing this minimum grade, plumbing codes aim to optimize drainage performance while ensuring that the pipe operates efficiently. This recommendation typically aims to strike a balance between sufficient flow rates and the practical installation of piping systems in various contexts.