Turn off power to the water heater
Set the gas control to pilot or off if it is a gas heater
Turn off the cold water supply valve
Connect a garden hose to the drain valve at the bottom of the tank
Run the hose to a safe drain location
Open a hot water faucet in the house to let air into the system
Open the drain valve on the water heater
Let the tank drain completely
Briefly open the cold water supply to flush out sediment if needed
Close the drain valve
Remove the hose
Close the open hot water faucet
Refill the tank by opening the cold water supply
Wait until water flows steadily from the hot faucet
Turn the power back on or relight the pilot if applicable