So his dad comes today and confirmed it is NOT a gravity fed system, and that there is most likely a blockage in the pipes affecting the water pressure. So we've written a letter to give to the real estate people tomorrow (but we'll be calling them first thing too, the letter is just for evidence). Also, his dad checked our smoke alarm (the condition of which was not noted on the inspection sheet and we told the property agent and she said just to test it and get back to her, which we were going to do today) and there isn't even a battery in it. We could have died in a fire last night because of her and her shoddy inspection.
I'm sure there'll be another update in this saga once we call the real estate people tomorrow. Sigh.