Problem with Noise from Tankless Hot Water Heater

By: Danny Lipford

I have sounds coming from our tankless water heater. Should I be concerned? -Nora

Hi Nora,

Gas tankless hot water heaters all make noise when firing up and heating water, but the levels are usually less than 90 decibels. A decibel meter can be used to find out how loud your tankless water heater actually is. If you have a smartphone, you can download a free decibel meter app called SoundLevel and measure the decibel output yourself.

If the noise occurs when hot water isn’t being used, there’s a good chance that another source is siphoning water from the line and creating a vacuum. If you hear a weird groaning sound from the pipes or the tankless hot water heater when you flush the toilet, that could be the culprit.

Even though a toilet only uses cold water, I have seen some toilets do this. In that case, you need to have a plumber install a check valve in the water line.

Good luck with your project,


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5 Comments on “Problem with Noise from Tankless Hot Water Heater”

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  • Clement Says:
    October 3rd, 2017 at 7:45 pm

    We just purchased a condo. The gas tankless water heater is in the garage and our master bedroom is right on top of it. The water heater makes very loud noise and we couldn’t sleep.

    Is it possible to install a switch to turn it off before we go to bed every night? Thanks.

  • john emilio paul andres Says:
    June 12th, 2017 at 10:15 am

    tankless hot water makes vibrating noise it works good just makes noise

  • Irina Says:
    October 9th, 2014 at 4:19 am

    Last night the water was way too hot and I woke up because of the very loud noise the water heater made, it sounded like the system was under high pressure, kind of laud singing pipes . I turned it off. What should I do?

  • donna Says:
    July 6th, 2014 at 4:20 pm

    Our water heater is considerably noisier than when we had it installed five years ago. Should I have a plumber check it? What could be causing this?

  • Roland Jugandi Says:
    March 23rd, 2014 at 10:22 am

    90 dB is very loud.

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Problem with Noise from Tankless Hot Water Heater