According to the Massachusetts Plumbing Code, what is the minimum size for a building drain?

The minimum size for a building drain in accordance with the Massachusetts Plumbing Code is 3 inches. This size is established to ensure adequate flow capacity for wastewater disposal, minimizing the risk of clogging and ensuring proper drainage from the building to the municipal sewer system or a septic system.

The 3-inch size is typically sufficient for most residential and light commercial applications, where the volume of wastewater generated can be effectively managed without causing line blockages. Larger diameters, such as 4 inches or 5 inches, may be required in special circumstances or for specific building types with higher waste flows, but the standard minimum requirement is set at 3 inches to cover the needs of typical installations while maintaining efficiency and function of the plumbing system.