I don't know which hotels you went to but that is bizarre. All water in Japan is safe to drink and, furthermore, is some of the best drinking water on earth IMO

I don't know which hotels you went to but that is bizarre. All water in Japan is safe to drink and, furthermore, is some of the best drinking water on earth IMO. You probably misunderstood, or perhaps the hotel staff were all sharing the same oddly wrong english handbook...