My gas water heater's pressure relief valve isn't sealing and releases ~3 gallons of water per hour outside the house. I'd like to shut the heater's water feed line OFF until I can buy and install a new valve. Is it safe to close the heater's supply valve overnight w/o turning off the gas? Or would that be like a time bomb?

  • 1
    why do you need to leave the gas on overnight?
    – Jasen
    Nov 19 '19 at 7:37
  • You may also need an expansion tank, depending on your water supply situation and why it's "not sealing" - it may be working correctly and sparing you a more dire problem, though in many cases they don't re-seal well once activated.
    – Ecnerwal
    Nov 19 '19 at 16:42

It's likely best to turn off both the water and gas supply. Risking running your water heater dry is not worth it.

  • Leaving the gas or electric supply to a water heater on with the water off is a great way to end up needing a new water heater instead of a new relief valve, indeed.
    – Ecnerwal
    Nov 19 '19 at 16:40

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