Step 2 · Shut Off Power and Water Supply
This is the most critical safety step. First, locate your home's main electrical panel (breaker box). Find the breaker that controls the water heater; it is usually a double-pole breaker labeled 'Water Heater' or 'WH'. Flip the breaker to the 'OFF' position. Next, find the cold water shutoff valve for the water heater. This is typically a lever or wheel-style valve on the cold water pipe entering the top of the tank. Turn the valve clockwise (for a wheel) or perpendicular to the pipe (for a lever) to shut off the water supply.