Turn off the water heater power
Shut off the gas supply or switch off the breaker
Turn off the cold water supply to the tank
Connect a garden hose to the drain valve
Run the hose to a safe drain location
Open a hot water faucet in the house
Open the drain valve on the water heater
Let the tank drain completely
Briefly open the cold water supply to stir up sediment if needed
Drain again until the water runs clear
Close the drain valve
Remove the hose
Close the open hot water faucet
Turn on the cold water supply and refill the tank
Open a hot water faucet until water flows steadily
Restore gas or electrical power
Check for leaks and proper operation