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

The primary function of a trap in plumbing systems is to prevent backflow of sewage. Traps are designed to hold a small amount of water, creating a barrier that blocks gases and odors from the drainage system from escaping into the living space. This is essential for maintaining a sanitary environment and protecting the health of inhabitants. The design of traps often includes a curved section that retains water, ensuring that this barrier remains intact as long as the trap is not dried out or broken.

This characteristic differentiates traps from other components in plumbing; while they do hold some water, their main purpose is not solely to do so but to serve as an effective seal against sewage gases. The other options focus on different aspects of plumbing systems. Options about providing a clean water source or eliminating noise in pipes, while related to plumbing, do not encompass the critical role traps play in preventing backflow and maintaining hygiene within residential and commercial buildings.