What is the correct grade to use when installing a sewer line?

The most commonly recommended grade for a standard 4-inch or 6-inch sewage pipe is from 1/8-inch to 1/4-inch per foot of pipe, though it differs by pipe diameter and location. Before installing any sewage line, check what the required pitch is in the local plumbing code.

Installing a sewage pipe with the correct grade is crucial. While liquids can get blocked in a shallow grade, if the pipe's slope is too steep the water flows too quickly to effectively carry solids away. To calculate the grade, measure the elevation from the start of the line to the end, and divide that result by the total length of the pipe.