Journeyman Plumber ExamDrainage, Waste, and Venting (DWV) SystemsMedium
A plumber is inspecting a newly installed 4-inch building sewer. What is the minimum required size for the cleanout fitting that must be installed at the junction of the building drain and the building sewer?
- A6 inches
- B2 inches
- C4 inches
- D3 inches
Show answer & explanationAnswer & explanation
Correct answer: C. 4 inches
Plumbing codes generally require that a cleanout fitting be installed at the junction of the building drain and building sewer, and its size must be at least the size of the pipe it serves, up to a maximum of 4 inches. Therefore, for a 4-inch building sewer, a 4-inch cleanout is required.
Why the other options are wrong
- A. While a 6-inch cleanout would work, it is larger than the minimum required by code for a 4-inch sewer.
- B. 2 inches is too small for a 4-inch building sewer cleanout.
- D. 3 inches is too small for a 4-inch building sewer cleanout.
Building Sewer Cleanout Size
The minimum diameter required for a cleanout fitting installed on a building sewer, typically at its junction with the building drain.
- Must be at least the size of the pipe it serves, up to 4 inches.
- Allows for clearing blockages in the building sewer.
- Essential for maintenance and inspection.
- Location and accessibility are also critical requirements.
Memory trick: Cleanout matches the PIPE, for a clear view, day and night!