water pressure guage

To check my pressure I connect my guage at the bottom of the water heater. My question is will it read the same there as on an outside outlet? Or does it not matter at all?

If no faucets are open, the pressure in a system should be pretty much the same everywhere. I'm not entirely sure if you put it in the system maybe 3 flights up if it would read the same as in the basement, but it might until you opened a faucet.