How old is the building, and does it have any galvanized iron pipe in the supply?
You may want to pick up a pressure gauge and measure what you actually have. They only cost about $10. Depending on where you place it, you may need some adapters. You can get it with a hose type fitting on it, but with adapters, can install it on a faucet, etc.
Within a very small amount in a low building, the pressure should be the same any place you test. If it changes considerably from static (no water running) to running, it may just be how the piping was run...the branches may be long, contorted, and too small.