What are the minimum slope requirements for horizontal drainage pipes of 3 inches or larger?

For horizontal drainage pipes that are 3 inches in diameter or larger, the minimum slope requirement is ¼ inch per foot. This slope is crucial for ensuring proper drainage and preventing sewage from stagnating within the pipes, which can lead to blockages, backups, and other plumbing issues. A sufficient slope facilitates the flow of wastewater by using gravity, allowing it to move efficiently towards the drainage system without pooling or slowing down. Thus, maintaining this minimum slope is a fundamental practice in plumbing work to uphold sanitation and system performance.