When to Close the Pressure Relief Valve While Draining a Hot Water Tank

After draining a hot water heater, do you reset the pressure valve before refilling the tank or after? -Desiree’

Hi Desiree’
It’s important to remember to close the pressure relief valve on the hot water heater when you are through draining it. Otherwise, water will run out the valve and through the discharge pipe once it refills.

Since the pressure relief valve vents at the top of the tank, you could wait until the tank is full before closing it, but it’s better to close it when you start refilling the tank in case you forget. Here’s how to go about it.

Once you’ve drained the tank as shown in our video on How to Drain a Water Heater

1. 1. Open the cold water intake valve for a minute to stir up and drain the last bit of sediment.

1. 1. Turn the cold water intake valve back off.

1. 1. Close the outlet valve at the bottom of the tank.

1. 1. Remove the hose from the outlet valve.

1. 1. Close the pressure relief valve.

1. 1. Open the cold water intake valve to refill the tank.

1. 1. Open a hot water faucet at a sink and allow it to run while refilling to release any air trapped in the tank.

1. 1. Once the tank is full, close the sink faucet, and check the discharge pipe on the pressure relief valve to be sure it isn’t leaking.

1. 1. If the valve leaks, see our article on How to Repair a Leaking Pressure Relief Valve.

1. Once everything is good to go, turn on the electricity or light the gas burner to heat the water in the tank.

Good luck with your project,