My son who lives in VA has a water gas water heater in his house that is probably 25 years old and still working well.

He will be leaving his house vacant for 6 months or more and is concerned about what to do with the water heater. We certainly don't want it to fail/leak while nobody is around. What is the best thing to do?

Should we shut off the water to the heater and shut off the gas?

Is the water heater inside the house, or in an unconditioned air location like a garage or attic? If in the house, will the house be heated while gone so the pipes/water heater don't freeze?

It's best to turn Off the water inlet & turn Off the gas. Does the heater have a drip pan below it with a drain pipe to the outside or to the plumming drain? The water heater could still possibly leak (low probability) even though it's Off.

Cheers, Tom

Thanks.
The water heater is in the basement which is not heated but the heat will be on at some low temp to be sure nothing freezes. In fact he HWH is right next to the furnace.

There is no drip pan but there is a sump (with sump pump) about 10 ft from the HWH. Not sure about the slope of the floor and if any leakage would find its way to the sump.

At least if the water inlet to the heater is off (as well as the gas), even if a leak occurs, it would only be whatever is in the tank.

Thanks again.

Be very careful about shutting off the inlet. Water expands and contracts with temperature change. Something has got to give. Normally this is accommodated by water flowing in and out of the inlet. Unless it is still connected to an expansion tank, shutting the inlet off stops the flow. The pressure valve can let excess water out, but I am not sure it can handle vacuum. You could leave a hot water tap open. Consider draining the tank. A closed volume of water could go foul in 6 months.

And yes, shut off the gas.

Thanks Labman.. Good thoughts about the expansion issue.

Is it OK to drain the tank? Will a drained tank rust more quicky?

I suppose draining the tank, shutting off the gas and the water inlet is the best option.

Let me add a bit to everyone's replies. Most water heaters are glass lined so rust won't be a problem. By all means drain the heater and shut the gas off.
If you're going away the best and cheapest insurance policy is to shut the water off to the house and drain the system down. Good luck, Tom