What is the minimum allowed slope of the bottom of a trench drain?

The minimum allowed slope of the bottom of a trench drain is crucial for ensuring proper drainage and preventing water accumulation. A slope of 1/8" per foot is the minimum angle that allows for water to flow effectively towards the drain outlets. This slight slope is typically adequate to utilize gravitational flow without requiring excessive force, allowing for efficient drainage of rainwater and other runoff.

Trench drains are designed to manage surface water, and insufficient slope can lead to water pooling, which can cause various issues such as erosion, structural damage, or deterioration of the surrounding area. A slope of 1/4" per foot or steeper can also be used and may be beneficial for specific applications, but 1/8" per foot is the minimum standard specified in many plumbing codes to ensure that drainage systems function effectively while complying with regulatory requirements.