Massachusetts Plumbers Journeyman Practice Exam

When rock is encountered during trenching, what depth below the grade line should it be removed to?

1. One foot

2. Two feet

3. Three feet

4. Four feet

The correct answer is: Two feet

When rock is encountered during trenching, it is important to remove it to a depth of at least two feet below the grade line. This depth ensures proper installation of the utilities being placed in the trench, allowing for adequate coverage and minimizing the risk of future issues such as heaving or instability. Removing the rock to this depth helps to create a stable foundation for the utility infrastructure and facilitates proper drainage around the installation. By adhering to this depth requirement, it also aligns with safety standards and best practices, preventing potential damage to both the utilities and the surrounding soil structure. In practice, if the layer of rock is shallow and minimally addressed, it could lead to inadequate backfill and problematic settling of the soil over time. This specific depth is commonly recognized in plumbing codes to ensure that all installations meet regulatory standards and maintain functional integrity.