Master Plumber Practice Exam

Providing cleanouts in long runs of horizontal drain piping is essential for maintaining the plumbing system's efficiency and allowing for proper access during maintenance and cleaning. The correct answer indicates that cleanouts should be installed every 50 feet.

This frequency is based on plumbing code guidelines that ensure accessibility for clearing blockages and performing inspections. In long stretches of drain piping, the likelihood of clogs increases, and having cleanouts spaced at regular intervals—specifically every 50 feet—ensures that a plumber can easily reach a blockage without needing to dismantle extensive sections of the piping. This practice not only saves time but also contributes to the overall functionality and longevity of the plumbing system.

Intervals longer than 50 feet might hinder effective maintenance, making it more difficult to clear blockages or maintain the system properly. Thus, having cleanouts every 50 feet provides a sensible balance between accessibility and practicality in drainage design.