What is the required fall per foot for a 4-inch sewer line?

The correct answer is 1/8 inch per foot for a 4-inch sewer line, a standard requirement according to plumbing codes. This specific fall rate is crucial in ensuring proper drainage and preventing blockages in sewer lines. A slope of 1/8 inch per foot means that for every foot of horizontal run, the pipe should drop 1/8 inch vertically, allowing for adequate flow by helping gravity move waste materials through the line efficiently.

In plumbing practice, if the fall is too steep, such as 1/4 inch or more, it can lead to water moving quickly through the pipe, allowing solids to settle and potentially cause blockages, which is counterproductive to effective drainage. On the other hand, a slope that is too shallow, such as 1/2 inch or a different measurement, may cause pooling and impede the flow, resulting in clogs. The 1/8 inch slope maintains a balanced approach, ensuring there is sufficient velocity in the water flow while still keeping solids in suspension and allowing them to be carried through the system.