What is the primary function of a trap in a plumbing system?

The primary function of a trap in a plumbing system is to prevent sewer gases from entering the building. Traps are specifically designed to hold a small amount of water which acts as a barrier between the sewer system and the living spaces of a building. When the trap is filled with water, it effectively seals off the opening to the drain, ensuring that no harmful gases or unpleasant odors can escape into the home.

This function is critical for maintaining sanitary conditions within a building and for the overall health and comfort of its occupants. The water in the trap needs to be periodically replenished, which typically occurs when fixtures are used regularly. If a fixture is rarely used, the water in the trap can evaporate, leading to the possibility of sewer gas infiltrating the living space.

Understanding the role of traps can help in diagnosing plumbing issues, such as unpleasant odors in the home, and underscores the importance of maintaining proper plumbing fixtures to ensure they function correctly.