How to drain a water heater

Posted on by Andrew LeVahn
draining a water heater

How to drain a water heater

How to drain a water heater

According to manufacturers recommendations you should drain your water heater annually to keep it working properly. This allows the heater to rid itself of debris and sediment that settles at the bottom of the tank.

To empty your water heater properly follow these steps:

1) Turn off the gas or electricity to the heater. If it’s a gas heater turn the knob to “pilot”. If you have an electric heater turn off the power at the main panel.

2) Shut off the water supply going to the heater. Your heater should have a shut off valve located on the cold water line running to the water heater. Normally it is located just above the heater and is either a round handle (like the picture below) or a lever handle. If it is a round handle turn it clockwise until it stops. If it is a lever handle you will only need to turn it a 1/4 turn so that the handle is pointing away from the piping.

water heater shut off valve

3) If you have access to a floor drain nearby you should hook up a hose to the drain valve located st the bottom of the heater. If you don’t have access to a floor drain you may have to drain it bucket by bucket (like the poor guy in the picture at the top of this post).

4) Before you start to drain the heater you need to open up the hot water side of a faucet located in the house. If you don’t do this step there will be a vacuum present in the line that won’t allow the water to leave the heater.

5) Open up the valve at the bottom of the heater to allow the water to drain out. (do not open the pressure relief valve located at the top of the heater) This is going to take between 20 to 45 minutes depending on the heater. Note: if using a floor drain make sure that it is working properly. The last thing you need is to clean up 40 gallons of hot water.

6) After the heater is finished draining shut off the drain valve. Also shut off the hot water tap that you opened earlier.

7) Turn on the cold water supply to the heater and allow it to fill up.

8) Turn the power or gas supply back on to the heater. The heater will take a while to heat back up again. There may be condensation that forms while heating back up so don’t be too worried if you see water dripping from your heater to start with.

9) Turn on hot water on a faucet in the house. You will have to allow the air to come out of the line before any hot water will come out. It’s going to sound funny and when the water finally comes it will shoot out with a burst but it will return to normal after a few moments.

Note: If you find that after draining your heater, one or more of your faucets aren’t running real smooth or have poor water pressure make sure that the aerator located at the faucets spout isn’t plugged with debris. It should unscrew by hand but if it doesn’t use a crescent wrench with a rubber jar opener to turn it off.  Using a jar opener allows you to grip the aerator without damaging the surface of the faucet or aerator.

Faucet aerator

For more info call us at 763-551-8990

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About Andrew LeVahn

I am the fourth generation of LeVahn's. I have been working at LeVahn Bros. since 1994. I went to Minnehaha Academy for high school and Bethel University for college. View all posts by Andrew LeVahn → This entry was posted in How to, Plumbing, Uncategorized and tagged , , , , , , , , , , , . Bookmark the permalink.

12 Responses to How to drain a water heater

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  3. Pingback: I have a dehumidifier. Is there a way to cap off the bucket once opened for a hose?

  4. Pingback: I have a dehumidifier. Is there a way to cap off the bucket once opened for a hose?

    • levahnbros says:

      There are expandable drain plugs that can be inserted into the tank if it’s just a hole in the tank itself. If you have a barbed fitting coming out from the tank and want to cap that fitting there isn’t anything specific for doing that. About all I could recommend for you to do would be to have a small section of hose coming off of the fitting with another fitting in the other end that is barbed by pipe thread. Then you could cap or plug the pipe thread end of the fitting.

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  6. Rusty says:

    I tried to drain my hot water heater but only a gallon or so drained out very slowly. If I toggled the pressure relief valve, water came pouring out (of the draining faucet). If I turned on the cold water supply, hot water came pouring out. I did have the hot water faucet open in the house. Any thoughts?

    • levahnbros says:

      I’m not sure why water doesn’t flow out. If you have the hot side of a faucet in the house open it should stop the vacuum effect that is created when the faucet is closed. Since you’ve already opened up the relief valve I would do it this way. Normally I don’t recommend doing it this way because occasionally the relief valve won’t close correctly after it’s been opened. The reason it pours out when you open up the cold water supply is because your homes water pressure forces the water out.

  7. Susan says:

    Hi,
    Thanks for this article. Like Rusty, water wouldn’t leave the tank unless the main was on. The drain valve is made of a whitish plastic but I noticed that near the tank, it looks a little yellower — might sediment be blocking the valve opening? If so, how do I clear it? My tank is a year and a half old, but the water is extremely hard, and I’ve already started hearing occasional popping from within the tank, suggesting sediment buildup.

    Thanks!

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  9. the idea of the rubber jar opener is so smart, I was trying to get the aerator off and everything just slipped, I never thought about using a jar opener!

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