Massachusetts Plumbers Journeyman Practice Exam

What should be the minimum size of the outlet pipe for an area drain?

1. A. 2"

2. B. 3"

3. C. 4"

4. D. 5"

The correct answer is: B. 3"

The minimum size of the outlet pipe for an area drain should be 3 inches. This size is generally sufficient to manage the flow of water typically collected by area drains, which are designed to prevent flooding and manage excess rainwater or runoff in outdoor spaces. A 3-inch outlet pipe provides a good balance between capacity and the potential for clogging, as larger pipes tend to be more prone to blockages from debris. Additionally, local plumbing codes often specify a 3-inch minimum to ensure proper drainage without creating an undue burden on the system. Choosing a smaller diameter could risk overflowing during heavy rain, while opting for a larger pipe may not be necessary and could complicate installation and increase costs without offering significant benefits.