What is the purpose of a trap in a plumbing system?

A trap in a plumbing system serves the essential purpose of holding a small amount of water, which creates a barrier that prevents sewer gases from entering the home. This water seal is crucial for maintaining indoor air quality and ensuring that unpleasant and potentially harmful gases do not escape from the sewage system into living spaces. Traps are typically located in drainage piping, and without them, odors from the sewer could permeate the home, causing not only discomfort but health hazards.

In addition to their primary function, traps also support the efficient draining of wastewater by allowing the passage of solids while retaining the water needed to maintain the seal. This is a fundamental component of plumbing that helps to keep homes sanitary and livable. Other options, while relevant to plumbing and water systems, do not accurately define the specific role of a trap.