We're are leaving home soon for a one week vacation. I plan to shut off
the main water supply and gas water heater. (We recently had a leak in
the pipe leading to the water heater. So I want to be safe).

Somebody also suggested that I open a hot and cold water faucet (after
shutting things off) and drain to release some pressuse in the system .
But I was also told that do this way it may create some vacuum in the
pipe system that might damage the pipes.

My questions:
1) Is it okay to just turn off the water supply and water heater
without releasing the pressure?
2) If not, is the vacuum a concern?

I searched the group and couldn't find a complete answer. Help will be
appreciated.