Thats easy - intermeadiate booster pumping stations at every 30/40stories. In tall buildings the pressure provided by a municipal water system is generally not sufficient to provide adequate pressure at the top of the building. As an example, municipal water systems typically provide maximum pressures in the range of 100 to 150 psi. This translates to buildings of 20 to 30 stories. Above this height the building will require a water pressure booster system.