What type of fitting is commonly used in drainage, waste, and vent systems?

In drainage, waste, and vent systems, various fittings serve specific functions to ensure the proper flow of waste water and ventilation of sewer gases. PVC elbows are commonly used to change the direction of pipes, enabling the installation of drainage systems in various configurations. Couplings are essential for connecting two sections of pipe, helping maintain the integrity of the drainage system. P traps are crucial for preventing sewer gases from entering living spaces, as they create a water seal that blocks gases while allowing wastewater to pass through.

Since all of these fittings—PVC elbows, couplings, and P traps—are integral components of drainage, waste, and vent systems, they work together to ensure functionality, safety, and efficiency. Therefore, the choice indicating that all of the mentioned fittings are commonly used in these systems accurately captures the comprehensive nature of the fittings utilized in plumbing.