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If I Cut The Water Supply To House Do I Need To Turn Off Hot Water Heater?

Cut the water supply and I can hear the hot water heater making noise. Will I damage it? I needed to turn off water because of a busted pipe and I can’t find a switch that turns off power just to hot water heater.

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  1. Comment by Dont touch that dial
    August 30, 2009 @ 11:55 pm

    For safety’s sake yes, turn off the hot water heater.
    If you can’t find the switch (it’s prolly a breaker in the breaker box/load center), turn off the power to the house.
    If the water drains from the hot water heater while it’s still on, you could be forcing a R/L test of the T&P valve.http://www.masterplumber.net/no_heat/stu…
    Did you watch MythBusters blow up hot water heaters?

  2. Comment by oldmanwi
    August 31, 2009 @ 5:01 am

    If anything should cause it to get empty. Like a leak or a siphon effect. it will build steam pressure and explode. It is better to turn it off and be safe.

  3. Comment by Bitter_t
    August 31, 2009 @ 10:28 am

    If its electric I would to be on the safe side. It should remain full and casue no issues but if it empties it will burn the heating element up. It gas its ok either way

  4. Comment by Kim B
    August 31, 2009 @ 3:52 pm

    if you shut off the water supply the water heater will still have water in it and should be fine unless you drained it, or ran hot water out of one the faucets in the house

  5. Comment by sensible
    August 31, 2009 @ 4:06 pm

    Most water heater electric shut-offs are controlled at the breaker box, not on or at the unit. If the water was going to be off for an extended period of time, I would shut it off.

  6. Comment by DudeMan
    August 31, 2009 @ 9:35 pm

    You do not need to turn off your hot water heater. They are designed to sustain if a pipe breaks, such as yours has.

  7. Comment by singstro
    August 31, 2009 @ 11:21 pm

    Not unless you think it might leak.

  8. Comment by brian777
    September 1, 2009 @ 6:17 am

    Yes, you should turn off the hot water heater. If you cannot find the switch for the heater then cut off all the power to the house until you fix the pipe.

  9. Comment by Green Eyed Girl
    September 1, 2009 @ 6:43 am

    No, it should be fine.

  10. Comment by fisherma
    September 1, 2009 @ 8:51 am

    yes, most definitely, your heating elements will burn out if they get expose to air. Look in your breaker box or fuse box for the power shut off to the water heater.

  11. Comment by keif_1
    September 1, 2009 @ 12:17 pm

    If your water is off for an extended period of time , then yes.
    Your heater can boil dry and then blow the heating element.
    Better safe than sorry, I would cut it off.

  12. Comment by aloneinb
    September 1, 2009 @ 1:04 pm


  13. Comment by Jason K
    September 1, 2009 @ 5:28 pm

    no its fine.

  14. Comment by eek
    September 1, 2009 @ 11:59 pm

    If the heater is making a noise turn down the thermostat on the hot water heater … it will usually be down near the bottom. You will need to be on hands and knees to find it.
    Put the setting on “vacation” or low. It should be okay if you get the pipe fixed promptly. If there is a delay.. turn than thermostat located on the water heater to “off.”

  15. Comment by Michael R
    September 2, 2009 @ 3:49 am

    You should have a switch in your box that goes just to the water heater (hopefully it is marked) and you will need to turn this off or you do risk damage to it. There may also be a switch on your water heater as well.

  16. Comment by fishlake
    September 2, 2009 @ 10:12 am

    Listen to ‘sensible’ and shut it off. The breaker in the circuit box for an electric heater , or the electric ignitor control on a gas or oil heater. The reasons are not only to prevent overheating or boiling dry, but risk of outright fire if it empties itself out through siphoning. A short period [less than a day or two] would be fine, but any longer and you should shut off the input/output valves to avoid siphoning when someone accidentally opens a faucet. Most faucets don’t seal well unless there is some pressure pushing against them.

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