Step 2 · Drain the System Pressure and Water Level
To relieve pressure in the system, go to a sink nearby (preferably on a lower floor) and open the hot water tap fully. Leave it open. Next, connect a standard garden hose to the drain valve located at the bottom of the water heater tank. Place the other end of the hose in a floor drain or run it outside. Open the drain valve by turning the handle or using a screwdriver. You only need to drain a few gallons of water, just enough to ensure the water level is below the height of the expansion tank connection. Once drained sufficiently, close the drain valve.