Homeowners can drain a Rheem water heater by turning off the power to the heater, shutting off the water supply and attaching a hose to the drain valve. If the bottom of the heater has sediment build-up, the user may have to flush the heater before refilling it.
Before draining the water heater, the homeowner should switch off the power of an electrical heater or turn a gas heater down to the lowest pilot setting. Attach a length of good quality garden hose to the water tank drain valve, as hot water running through a poor quality soft hose may cause it to leak. Run the other end of the hose to a basement floor drain, sump hole, an area outside the house or a strong plastic bucket. Close the cold water supply valve, and open the pressure relief valve, as well as the hot water side of the nearest tap. Open the drain valve, and empty the tank.
To flush any sediment out of the tank, close the drain valve, open the cold water intake valve, allow the tank to refill, and then empty it again. If there is a lot of sediment, refill and drain it a few more times. When the tank is clean enough, shut the drain valve, refill the tank one more time, close the pressure relief valve, and turn the electricity or gas heat back on. Homeowners should flush hot water tanks every six months to a year.