Rhode Island Journeyman Plumber Practice Exam

A sewer must be buried a minimum of how many feet below grade?

1. 2

2. 3

3. 4

4. 5

The correct answer is: 3

When determining the appropriate depth for burying a sewer line, it's crucial to consider various factors such as local regulations, frost line depth, and soil conditions. The minimum depth of three feet below grade is commonly required to prevent damage from surface activities and to protect the sewer from freezing temperatures in colder climates. This depth also helps to ensure that the sewer line is not susceptible to disturbances from surface loads or potential excavation activities. Furthermore, adhering to this standard aids in maintaining proper drainage and reduces the risk of sewage backups or blockages due to external pressures. Understanding this requirement is essential for compliance with plumbing codes and for ensuring the longevity and reliability of the sewer system.