What is the recommended slope for a building drain?

The recommended slope for a building drain is a minimum of ¼ inch per foot. This slope is designed to ensure that wastewater flows effectively and efficiently through the drain, reducing the chances of backups or clogs. A slope of ¼ inch per foot provides a balance between adequate drainage and minimizing the potential for erosion or excessive velocity of flow that could lead to noise or damage to the piping system.

Maintaining this minimum slope is crucial for gravity drainage systems, as it helps promote a consistent flow of water and waste while allowing for the natural settling of solids. Should the slope be too shallow, it could lead to pooling of water, while a steeper slope might result in turbulence that can hinder effective drainage and lead to other issues in the plumbing system. This makes the ¼ inch per foot slope a widely accepted standard in residential plumbing practice.