In the past, when I am spending more than several days away from home, I have always shut off the main water to the house and turned the water heater (gas) down to 'vacation' mode. I have heard horror stories about leaking pipes when people were away for days on trips. I am now wondering if this is a bad idea. Am I somehow creating a dangerous situation with the water heater? I have no experience turning on/off the water heater and worry about dealing with the gas should I turn it completely off. I am not sure what to do at this point for my next trip.
I didn't know if there would be concern about water being pulled from the water heater into the system, for whatever reason (I have heard of something about pressure in the lines or lack there of). If there is no water circulating through the tank, does the water level drop over time? What happens to a gas water heater if has no water in it? Does it just act as a storage tank if it is on 'vacation' and the water main is turned off?