One way to extend the life of your Rheem water heater and keep it running efficiently is to periodically drain and flush the tank. Over time sediment builds up inside the tank, which can cause performance issues. The interval between flushing depends on the hardness of your water. Most water heaters benefit from a flushing once a year. Flushing a Rheem water heater is much like any other brand.
Turn off the electrical supply and gas supply to the hot water heater. The circuit breaker is inside your home electrical panel. On the Rheem gas water heater, the gas shut off valve is on the lower front of the water heater.
Rotate the cold water supply shutoff handle clockwise with your hand to stop the water flow to the heater.
Thread a garden hose onto the drain valve on the water heater tank. The drain valve on most Rheem water heaters is on the lower part of the tank usually to the right of the gas valve or lower electrical panel door. Place the opposite end of the garden hose in a nearby bathtub or outside through an exterior door. Keep children and pets away from the garden hose while the tank is draining.
Turn the hot water on at the nearest faucet to the water heater. Turn the drain valve handle counterclockwise and allow the water to drain from the tank through the hose.
Open the cold water supply when the water has completely drained from the tank. Allow the water to flow through the tank and garden hose until the water runs clear.
Close the drain valve slowly and allow the tank to fill with water. Once the water flows steadily through the open faucet, turn the faucet handle off.
Allow the water heater tank to fill completely and remove the garden hose from the drain valve. Turn on the electrical and gas supply. Relight your pilot light as directed in your Rheem owner's manual for your model.