Once all the connections are made, it's time to fill the water heater up with cold water and turn the unit on.
- Turn on the cold water supply valve to the water heater and turn on the main water supply valve at the water meter if that was also turned off.
- Close the faucet near the water heater that was opened when you drained the water heater.
- Fill the water heater tank. One way to check when it is full is to turn a hot water faucet on in a remote bathroom or the kitchen and when water comes out of that faucet, the tank is filled. The water will still be cold.
- Once the tank is filled turn power back on at the power panel by reinstalling the fuse or resetting the circuit breaker (if an electric model); If a gas model, make sure the main gas valve is opened and light the pilot.
- Set the thermostat to a temperature between 110 and 130 degrees.