Home Inspection State Practice Exam 2025 – 400 Free Practice Questions to Pass the Exam

The primary purpose of a plumbing trap is to prevent sewer gases from entering the home. A trap, typically designed as a U-shape, holds a small amount of water at all times. This water acts as a barrier between the open air and the plumbing system. When wastewater flows through the trap, it fills the curve, ensuring that the sewer gases— which can be harmful and give off unpleasant odors— do not have a clear path into the living space.

While the other options all relate to plumbing systems, they don't align with the trap's main function. For example, plumbing traps do not facilitate easy cleaning of pipes; they are primarily a safety feature. Similarly, traps are not designed to filter out debris— that task falls to other components in the plumbing system. Lastly, maintaining water pressure is not a function of the trap either, as that is reliant on the design of the larger plumbing system and the water supply pressure. Thus, the trap's essential role is to safeguard indoor air quality by blocking unpleasant and potentially hazardous gases from the sewer.