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

In a waste and vent system test, the pressure required to hold a specific column of mercury is typically established through industry standards and safety protocols. The correct choice specifies 15 P.S.I.G., which corresponds to the necessary pressure to ensure the integrity and functionality of the system during testing.

Applying the right amount of pressure is crucial for identifying any potential leaks or weaknesses within the system. A higher pressure can ensure that the test is comprehensive, allowing for a complete assessment of the system's performance under conditions that mimic real-life usage scenarios.

When conducting the test, maintaining this level of pressure confirms that the waste and vent system will operate safely and effectively, preventing backflow or other issues that could cause problems in the plumbing system. Ensuring that the pressure is maintained at this level provides a reliable margin for safety and compliance with plumbing codes.