CSLB Class B General Contractor's License Practice Exam

What fitting is typically used to connect the building drain to the building sewer?

1. Expansion joint

2. Coupling

3. Cleanout

4. None of the above

The correct answer is: Cleanout

The fitting that is typically used to connect the building drain to the building sewer is a cleanout. A cleanout provides access to the drainage system, allowing for maintenance and clearing of blockages. Proper installation of a cleanout is critical as it enables plumbers to clean out debris and inspect the pipe’s interior without having to disassemble the entire system. While expansion joints and couplings are important fittings used in plumbing, they serve different purposes. An expansion joint accommodates movement and thermal expansion, whereas a coupling is used to join two lengths of pipe together. Neither of these fittings provides the necessary access that a cleanout does, which is essential when it comes to maintaining a clear and functional drainage system. Thus, the cleanout represents the correct choice for connecting the building drain to the building sewer, as it facilitates both functionality and maintenance.