Red Seal Plumbing Practice Exam

Which of the following must the base of every soil or waste stack contain?

1. Cleanout and expansion joint

2. Vent stack

3. P-trap

4. Overflow pipe

The correct answer is: Cleanout and expansion joint

The base of every soil or waste stack must contain a cleanout and expansion joint. It is important to have a cleanout, which allows for easy access to remove any clogs or debris. An expansion joint is also necessary to allow for movement and prevent damage due to shifting or settling. The other options listed are not necessary for the base of a soil or waste stack. A vent stack typically extends above the roofline and helps to maintain proper air pressure and prevent potential blockages. A P-trap is typically located under a sink and traps debris to prevent clogging and sewer gases from entering the building. An overflow pipe is used in plumbing fixtures, such as a bathtub or sink, to prevent flooding in case of a clog or blockage. However, these components are not required for the base of a soil or waste stack.