How to Flush a Water Heater

Remove the old valve

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Photo 1: Remove the valve

Remove the old valve. If it breaks off, saw the broken portion with a hacksaw blade until you hit metal threads. Then use a hammer and screwdriver to chip out the pieces.

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Photo 2: Assemble the new valve

Remove the handle from the ball valve so you can assemble all the 3/4-in. fittings.

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Photo 3: Flush

Install the new ball valve and flush the sediment into a bucket. Let the water flow until it runs clear.

Draining sediment several times a year is an effective way to reduce energy costs and increase the life of your water heater. Unfortunately, most water heaters come with crummy valves. And once you open them to drain the sediment, the debris clogs the valve, keeping it from sealing. But you can replace the crummy factory drain valve with a full-port ball valve. The actual valve replacement takes about an hour, but sediment buildup may slow the draining process. So set aside a full morning for this project.

Start by shutting off the water heater's power or gas supply. Open any hot water faucet until you run out of hot water. Leave the faucet on, close the cold water valve to the tank, and then hook up a garden hose to the valve to drain the tank. After the tank drains completely, unscrew and remove the valve by turning the plastic nut behind the knob. If the valve breaks, don't panic (see Photo 1). Stick a wire coat hanger through the opening to break up the sediment. Assemble the new valve (Photo 2), shut off the faucet and reopen the cold water supply valve to flush out the tank (Photo 3).