What is the minimum diameter required for clothes washer standpipes?

The minimum diameter required for clothes washer standpipes is 2 inches. This size is crucial for several reasons. Firstly, a 2-inch diameter allows for adequate drainage capacity to handle the high water flow that can occur when a washing machine empties. It helps prevent clogs by reducing the likelihood of buildup and facilitates proper drainage, as the larger diameter can accommodate the rush of water without overwhelming the system.

Additionally, plumbing codes typically specify the size to ensure that the plumbing system can manage the discharge from the washer efficiently. Using a smaller diameter, such as 1 inch or 1.5 inches, could lead to potential drainage issues, increased risk of backflow, and potential violations of plumbing codes. The requirement of 2 inches ensures compliance with these standards, promotes effective functioning, and maintains the longevity of the plumbing system.