Water Heaters - Dormant Water Heater

I have a 7 yr old tank that is not being used, but is connected to the piping.
The tank will be unused for at least a year. - (It's for a vacant Apartment). The Propane has been turned off.
Should I drain the tank or leave it full of water? I flushed it recently to get the crud out, but was unsure if it mattered if it remained full or not.
Thanks, Vince.

Thats a tough question. Never thought about it to be honest. I know in a situation with washers it is better to leave water on em so they don't dry out and crack..but no washers inside a water heater. I can't think of any parts inside a gas heater that might dry out other then a dip tube....course could start rust to start building up with no water in it.

My vote: Leave full of water.

Scientific answer: No clue.

Maybe call a water heater manufacturer and ask their customer service.

I agree with CSG...call the company. But my take would be this: It is generally bad practice to have non-circulating water. Even a dead-end run of pipe can stagnate, and inspectors usually will not allow such arrangements. Would be very leary of a tank full of non-moving water for a year. I would drain the tank and leave the drain open and the hot/cold nipples at the top also open. Maybe tape a piece of window screeining in place to exclude insects. Also, disconnect the gas, remove the gas stop valve and cap the pipe. This is the safest thing to do for a year. Before reusing, flush well with a mild bleach solution.