Massachusetts Plumbers Journeyman Practice Exam 2026 - Free Plumber Journeyman Practice Questions and Study Guide

The correct size for waste outlets serving shower stalls and compartments that are not part of bathtubs is 2 inches in diameter. This standard is established to ensure that the drainage from the shower is efficient and effective at preventing clogs. A 2-inch diameter allows for adequate flow of waste and water, accommodating the volume that is typically discharged from a shower.

Using a size smaller than 2 inches could lead to drainage issues, as it may not handle the waste flow and could become easily clogged over time. On the other hand, larger sizes like 3 inches or 4 inches are typically not required for shower stalls, as they may lead to unnecessary costs and complications in the plumbing system without providing additional benefit in terms of drainage for a shower setup. Therefore, the regulation for the 2-inch diameter is designed to balance efficiency and practicality in plumbing design.