My gas water heater, continuously lets hot water out from the outlet (seems it is connected to tp valve, it goes through the wall to outside the home).

If I turn the water heater to low (much below the normal setting with the recommended arrow), it stops after a few minutes.

What could be the problem and I am worried if this is something dangerous, in addition to wastage of water and gas..?

Also, I noticed that my heater is making more noise than ever..It is a 3-4 years old heater..

  • 1
    What is the temperature of the water coming out of the over flow? It could be the thermostat is not shutting off the burner. This is not a normal DIY job; it's a professional repair. Aug 25, 2018 at 21:14
  • thanks, I didn't check the temperature but it was hot water..I think this is potentially the thermostat as I don't see it ever shutting off.. but wait, if I lower the temperature, it shuts off..confused.. Aug 25, 2018 at 22:12
  • The thermostat is probably not working correctly. AFIK the thermostat is part of the gas valve assembly and competent replacement by an experienced tech is recommended. This is not a system to learn on. Aug 25, 2018 at 23:18
  • @JimStewart - got it, reaching out to a professional soon. Thanks Aug 26, 2018 at 17:27

1 Answer 1


The water pressure in the house may be too high. These valves usually can be bought with a discharge over pressure of 125 or 150. Check the pressure in your house. However these valves only leak or blow off above a 210 degree water temp. You may need a domestic expansion tank and/or a whole house PRV. If in doubt or you do not feel safe checking this tank, I would call a licensed professional (plumber) for help.

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