In a large building the pressure would generally be higher in the lower floors as there’s more water ‘leaning’ on it from all the floors above it. However as there are safety regulations for the maximum pressure at any point in the system, they often use pressure valves to make sure it will not rise above a certain pressure (eg 75 psi). So that way you generally won’t notice a difference between the floors in a building. In a small building without pressure valves it’s true that the lower floors will have the highest pressure.