What is the function of a trap in plumbing?

The function of a trap in plumbing is to hold water and prevent sewer gas from entering a building. Traps are designed with a U-shaped bend that retains a small amount of water at all times. This water acts as a barrier against gases and odors that can escape from the sewer system. By maintaining this seal, traps play a crucial role in ensuring that harmful and unpleasant sewer gases do not infiltrate living spaces, thereby promoting a healthier and more comfortable environment.

The other choices describe functions that are not relevant to the specific role of a trap. For example, connecting multiple pipes typically involves fittings like tees or elbows rather than traps. Increasing water pressure is accomplished through pumps or pressure regulators, not by traps. Lastly, while debris can be filtered out through devices like strainers or screens, traps do not serve this purpose; they are solely focused on maintaining the water barrier.