This diagram shows a washing machine drain connected to a standpipe with a built-in P-trap. The standpipe is connected to a vertical drain pipe using a sanitary tee fitting. The washing machine's hose enters the standpipe, which must extend at least 6 inches above the trap. This elevation ensures that discharged water does not overflow. The P-trap prevents sewer gases from escaping through the standpipe. The standpipe must be tall enough and properly secured to handle the high-pressure discharge from a washing machine. This type of setup is typical in laundry rooms and utility areas. It requires compliance with specific plumbing codes, including pipe diameter, height, and cleanout access. The illustration emphasizes the critical spacing and height needed to prevent flooding or improper drainage. This is a textbook example of properly vented and trapped laundry waste systems.