There is a water tower on the top floor. Will the water pressure on the top floor be lower?

Not necessarily. There is a water tower on the top floor, and the water pressure on the top floor may be quite high. Because the water pressure depends on the height of the water tower, the capacity of the water tower, the position of the water pump, the diameter of the water pipe and many other factors. The water tower on the top floor has enough height, large capacity, low pump position and suitable pipe diameter, so the water pressure on the top floor will be higher. If there are the above problems, or the water pipe is partially blocked, the water pressure on the top floor will be relatively small.