I have to do a water heater flush. From what I read, most websites said to leave water heater on pilot also leaving the gas on. Is this even safe? would the water heater kick on when draining if left on pilot? will the tank be damaged if there is no water in the tank if left on pilot?

3 Answers 3


Yes it is safe to leave the water heater in pilot mode while flushing. You do not want the burner to fire while the tank is empty as this can damage the tank but the pilot will not cause a problem. Added: most gas valves with a standing pilot have the temp setting and “pilot” then off settings. Rotating to the pilot mode will keep the burner from turning while flushing. Some valves have a button to push to go into pilot mode. For gas models with igniters just turning the valve off is fine as it will relight automatically.

  • 1
    Perhaps you could explain how to insure the burner does not fire up when draining the water heater. I would surmise by reading the question that oliveoil10 does not know what Pilot Mode is.
    – Alaska Man
    Apr 19, 2020 at 20:04

I agree with the others and will go a whole lot further to how a flush is actually done right...not the silly YouTube and Internet majority way. Don't do much of anything that you plan for just a flush.

If you aren't moving the tank nor replacing the T&P valve nor Anode Rod. Then, just open the drain valve, once your hose is attached.

A Drained-Flush does very little to remove much of anything and you should use the water pressure to your benefit to shoot, blast and drag sediment out.

You can then also shut the cold water inlet valve while the drain is open to cycle that opened & closed. To stir-up any remaining debris and re-pressure behind big chunks, to blow them into the drain valve where you can crush them by opening and closing the drain valve on them.


I have flushed (NOT drained) my heaters several times with the pilot and burners on, no problem.

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service and acknowledge that you have read and understand our privacy policy and code of conduct.

Not the answer you're looking for? Browse other questions tagged or ask your own question.