Are there any tricks to drain a tank-style water heater?

Or is it as simple as attaching a hose to the small drain pipe and then opening the valve?

Some web references have said you need to open up another valve somewhere so that air can enter in order to allow it to drain, whereas other web references make no mention of this.


Make sure it's off (power/gas and water supply). Open a faucet (upstairs) and put a towel under the bottom valve before working on it (just in case). After the tank is empty, open the water supply again (for a minute maybe) to flush out any sediment.


Be sure to turn off the power at the breaker. Then just turn off the cold water supply and also the hot water feed. It will drain. If it is draining too slow, crack the pressure relief valve and that will let more air in, but usually it will drain fine by itself. Be prepared to see some nasty stuff. Flush it with cold water a couple of times once it is empty to help clean more sediment off the bottom. Open the hot and cold valves on the heater, and at least one set of faucets at a fixture in the house when you fill it again. Wait until the tank is full and water is flowing clear with no air pockets at your faucets before turning power back on. Never turn on electricity to an empty or partially-filled water heater, or it will burn out your elements.

  • 4
    If you're feeling adventurous, draining the tank provides a good opportunity to check/replace the sacrificial anode in the tank as well. Keeping a good anode will help the tank last longer.
    – JS.
    Aug 2 '16 at 22:09

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