Step 2 · Turn Off the Cold Water Supply
Locate the cold water supply pipe entering the top of your water heater; it is often marked with a blue ring or handle. Find the shut-off valve on this pipe, which will either be a wheel-style gate valve or a lever-style ball valve. Turn the wheel-style valve clockwise until it stops. For a lever-style valve, turn it a quarter-turn so the handle is perpendicular to the pipe. This stops new water from entering the tank as you drain it.