Just to mention as I think many forget,
You have a 50 gallon or more supply of water
in the hot water tank.
If water service is disrupted and gets shut off,
you first need to turn the gas off to the hot water tank (or electric)
and then to access the water,use a hose on the bottom
drain valve. Its clean water,maybe a little rich with rust
if you have an antique heater.