How do you replace the drain valve in a gas water heater?

Many water heaters have plastic valves that break due to heat and pressure. Replace the valve to stop leaks and prolong the life of the tank. In addition to a replacement brass valve, gather Teflon pipe tape and an appropriately sized wrench to fit the valve.

1. Turn off the gas and water

   Turn the gas valve on the tank to the off setting before proceeding. Look for a valve at the water connection on the top of the tank. Turn off the water. If there is no water valve, turn off the water main into the home.

2. Drain the tank

   Connect a garden hose to the valve. Open the valve and the pressure relief valve at the top of the tank. Allow all the water to drain from the tank before proceeding. Disconnect the hose.

3. Remove the old valve

   Use the wrench to remove the old valve. If the plastic valve breaks, use a 5/8-inch drill and an electric drill motor to remove the valve remains from the tank.

4. Install the new valve

   Wrap the threads of the new valve with the Teflon tape. Install the valve by hand until snug. Tighten with the wrench.

5. Start the water heater

   Close the pressure relief valve. Turn on the water. Open a hot water tap inside the home, and allow the tank to fill with water. Turn off the tap. Follow the manufacturer's directions for relighting the gas pilot.