I have a 3 storey apartment block that has very poor water pressure and also poor hot water temperature. It can't be caused by the new 5 star rated taps, so what could possibly be our problem in this block?

How old is the building? What type of pipes? Copper, plastic or galvanized? Did the pressure drop happen all of a sudden or did it come on gradually? Is the hot water furnished by just one water heater? Let me know, Tom