What is the minimum slope required for an above-ground waste pipe?

The minimum slope required for an above-ground waste pipe is 1/4 inch per foot. This particular slope is crucial for ensuring that wastewater flows effectively through the plumbing system by utilizing gravity. A slope that is too shallow, such as 1/8 inch, may not provide sufficient downward angle for the waste to continually move towards the drain, leading to potential blockages and backup issues. Conversely, slopes that are too steep, such as 1/2 inch, can cause the wastewater to flow too quickly, preventing solids from being adequately carried away and resulting in sediment buildup. Maintaining the appropriate 1/4 inch slope strikes a balance that allows for efficient wastewater transportation while minimizing the risk of clogs.