What is the minimum slope required for a 3-inch drain pipe?

The minimum slope required for a 3-inch drain pipe is 1/4 inch per foot. This slope is recommended to ensure proper drainage and prevent clogging. A slope that is too flat may allow waste and water to settle in the pipe, which can lead to blockages over time. The 1/4 inch per foot standard is effective in maintaining flow velocity, allowing liquids to carry solid debris away without accumulating. This guideline is widely accepted in plumbing codes and practices, ensuring that drainage systems function efficiently and reliably.