What is the chief purpose of a plumbing system trap?

• A. To provide drainage
• B. To prevent backflow
• C. To provide water seal
• D. To simplify maintenance

Answer: (C)

The chief purpose of a plumbing system trap is to provide a water seal. Traps are designed to hold a certain amount of water, which creates a barrier that prevents gases and odors from the sewer or waste system from entering the living space. The water in the trap acts as a seal that blocks these potentially harmful gases while still allowing wastewater to flow through the plumbing system. This essential feature not only helps maintain a sanitary environment but also contributes to the efficient functioning of the plumbing system by preventing unpleasant odors from escaping into occupied areas.

While drainage, backflow prevention, and maintenance are important aspects of plumbing, they do not capture the primary function of a trap as effectively as the provision of a water seal does.