What is the purpose of a trap in plumbing systems?

The purpose of a trap in plumbing systems is primarily to protect against sewer gases. Traps are designed to hold a small amount of water, which creates a seal that prevents harmful gases, such as methane and hydrogen sulfide, from escaping from the sewer into the living space of a building. This is crucial for maintaining a safe and healthy indoor environment, as sewer gases can be both dangerous and unpleasant.

Moreover, this water seal only has a minor impact on overall drainage speed and does not serve to enhance it directly. Traps can also create some noise as water moves through the plumbing, but this is not their main function. Similarly, while traps can influence water usage in an indirect manner by maintaining functionality in drainage, reducing water usage is not their primary purpose. The main function remains the blocking of sewer gas entry through the water seal they provide.