Its only one floor. I have not measure anything yet. But from the basement floor to the celing is about 9' then a couple more feet to get through to the main floor, then all the way up to the top of the tank would be about another 5'?? So I was rounding up at the highest but I would say w/o measuring we would be looking at most 20', but probably more than likely 15-16'. Does that not sound right? I know I need to firm up measurements on things but 20' while a bit much is on the conservative side when figuring the head distance.