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OK to leave on hot water heater, even if water is turned off?

Posted by swampwiz (My Page) on
Sun, Apr 18, 10 at 16:26

This is going to sound a bit strange, but let me explain. I am someone who goes away from my house for LONG periods of time. When I do return (which is always after a long transcontinental flight or a long drive), of course, I like to be able to take a hot bath.

For my old home, as the cost of water for non-usage was only about $7/mo, and the longest I would be away was 3 months, I just let the water stay on. However at my current location, since the water is unmetered, there is a flat cost to everyone in my city of $40, irregardless of how much water is used - so I will be cutting off the water when I leave and simply getting it hooked up before I would be ready to return (the charge for rehookup is only $10.) As for the gas for the hot water heater, since the cost to rehookup is exhorbitant and the cost of using no gas is relatively low, I will just leave it on. I suppose that I could turn off the hot water heater as well, and just drain it, but then I wouldn't have the hot water when I would return (although I suppose that I could power it up and wait a few hours to take that first hot bath.)

Anyway, I would prefer to just leave the hot water heater, with the water between the heater and the hot water faucets intact. I would have to suppose that being the hot water line, I should have no problem with freezing of pipes, like I would with the cold water line (Should I be concerned? The climate is Gulf Coast with the worst case being lows down to 10F with a total freeze time of maybe 48 hours.) But even without the possible freeze problem, I wondering if there would be any other problem with the main line valve being turned off. It would seem that the water that would be past the main line would just stay in the pipe (and being underground would not be a problem.)

Are there any other aspects of this situation that I should be concerned about?

Follow-Up Postings:

RE: OK to leave on hot water heater, even if water is turned off?

Are you saying that when you return, you will contact the water supplier for reconnection, wait until they restore the service but after that, waiting until the water gets hot enough to use is not acceptable? It would take about an hour to heat.

RE: OK to leave on hot water heater, even if water is turned off?

How hard is it to turn it on?
I suppose that you could turn off the hot water heater, and leave it full.
Or drain it, too, to flush it, which is a healthy thing to do.
And you could flush it a few more times once you get back to it and get water pressure again. Also a healthy thing to do.


RE: OK to leave on hot water heater, even if water is turned off?


The answer to your question is that the best thing to do would be to at least turn your gas water heater to "pilot".

Here's why: It won't use any gas keeping the tank warm for three months while you are gone. The other reason is a little more esoteric... if your water is turned off at the supply, the water has no where to expand when it's heated unless you have an expansion tank. This can cause the pressure valve to open enough to reduce the pressure.

Turn the water heater to pilot when you leave... it will only take about 30-40 minutes to heat when you get back home.

For electric water heaters, I suggest shutting off the power if the water is off. If the water level gets below the top element it will burn out.

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