What is the minimum drain size required for a residential laundry?

The minimum drain size required for a residential laundry is 1 1/2 inches. This size is specified in the Massachusetts Plumbing Code to ensure that the drain can adequately handle the wastewater produced by washing machines, which typically discharge large volumes of water quickly. A 1 1/2-inch drain provides sufficient capacity to prevent clogs and allows for efficient drainage during the washing cycle.

Factors such as the potential flow rate of the washing machine and local plumbing conditions are considered in determining this minimum size. Using a drain that is too small can cause backups and slow drainage, leading to potential sanitation issues. Therefore, the code mandates this size to ensure proper function and minimize the risk of plumbing problems within the home.