Arizona Plumbing Practice Exam 2026 – Complete Preparation Guide

The purpose of a P-trap in a drain system is primarily to trap debris and prevent clogs. The P-trap is a U-shaped section of pipe that holds a small amount of water, which creates a barrier between the drain and the plumbing system. This water seal helps to trap debris that might otherwise travel down the drain and accumulate further along the plumbing, potentially leading to blockages. Additionally, the water barrier prevents sewer gases from escaping into the home, maintaining a safe and sanitary environment.

While the P-trap does help in catching some solid materials as they flow through the system, its main role is to maintain that water seal, which is crucial for both function and safety. The design of the P-trap ensures that any floating debris or heavier particles are captured before they can continue through the drainage system, mitigating the risk of clogging and maintaining the efficiency of the plumbing.