Step 4 · Open a Hot Water Faucet and T&P Valve
To prevent a vacuum from forming inside the tank, which would slow or stop the draining process, open a hot water faucet in your home. The faucet in a nearby utility sink, kitchen sink, or bathtub is ideal. You will hear air being drawn into the faucet as the water level in the tank drops. Additionally, it is wise to open the temperature and pressure relief (T&P) valve on the side or top of the tank by lifting its lever. This will also help introduce air and speed up draining.