What is the minimum diameter of a trap required for a residential automatic washing machine?

The minimum diameter of a trap required for a residential automatic washing machine is 2 inches. This specification is important because it ensures there is adequate flow rate and minimizes the risk of clogging due to the discharge from washing machines, which can contain lint, detergent, and other debris. A 2-inch trap provides the necessary volume to handle the wastewater efficiently, preventing backflow and maintaining proper drainage performance. Choosing a diameter larger than this is not typically required for standard residential applications, while a smaller diameter could increase the likelihood of blockages, thereby compromising the drainage system's effectiveness.