Sorry if this question has already been asked but I have a random question about my water heater to see if this is anything I need to be worried about. To start off I live in an apartment complex and my water heater is in a locked utility closet. I have noticed everytime I flush the toilet and make my way to the other end of the house I hear a "clicking" sound coming from the heater as the toilet fills back up with water. That is the ONLY time I ever hear the sound is right after a flush and it stops right after the water stops filling the tank. I have a gas heater and the sound is almost like a election lighter on the stove top when you turn on a gas burner. However I do know the water heater has a pilot light and it is working just fine as I hear it ON (the gas burning sound) every once in a while. Any ideas what might be causing the clicking sound?

UPDATE 2/28 - I just checked and the water in the tank is cold, both after sitting all day and right after a flush so I dont think it is hot water coming into the tank. I'm kinda stumped right now but I am off on tuesday and going to make an appointment to see if the maintenance can do anything to fix it?? hopefully they can.

  • Is your toilet hooked up to the hot water instead of cold? There is no reason that the hot water heater should be affected when you use cold water.
    – Ethereal
    Feb 27, 2014 at 14:20
  • Call your landlord, have him have someone look at it. Could be other things in the utility closet making the noise. It is possible that your toilet fill valve is connected to your hot and cold water supply. Some people do this to prevent the tank from sweating in the summer. Feb 27, 2014 at 14:35
  • @OrganicLawnDIY - Wax ring could melt then right? Doesn't make sense to hook up the hot.
    – DMoore
    Feb 27, 2014 at 14:44
  • 3
    Any chance the water meter is also in the same area as the water heater?
    – Tester101
    Feb 27, 2014 at 16:35
  • 1
    @DMoore hot and cold through mixing valve, not just hot. Feb 27, 2014 at 18:38

1 Answer 1


The click-click-click sound is probably coming from the water meter.

Check if it makes the same sound when you run COLD water, in a kitchen sink, for example.

Sometimes a mixing valve is used to put some hot and some cold water into the toilet tank to prevent or limit the tank sweating in the summertime. The mixing valve is adjusted to "temper" the water by adding just enough hot water to raise the temperature of the water in the tank from cold, to I'd say "lukewarm", but not hot. The water is then much closer to room temperature, so it won't "feel" hot, or even particularly warm. If a mixing valve is installed and the water feels hot or even particularly warm, or even on the cold side, the valve needs to be adjusted.

In either case, cold water only, or a mixture of hot and cold, some water meters just "click" as they measure the amount of water flowing through it.

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