The point here is ..even if the person has a preffered drink other than water.The problem is still solved.It does not affect the positioning of any of the nationals.The puzzle is solved if it satisfies all the conditions given mutually as well as in exclusivity period.German is the answer.We can go on arguing about 10 flaws in the question to say the question is unsolvable .but the question itself says its solvable ...2% or 100% its solvable!"just as no one expects to find a person that drinks exclusively coffee"
This is actually my point exactly... Thank you. It is not stated that they drink their personal beverage exclusively at the exclusion of all other drinks, just that it is different from what the other four drink. You are right, you would not find a person who drinks only coffee (maybe beer, haha, funny). Therefore, a logical person would conclude that they ALL still drink water from time to time.
It does state that their beverage preferences (when it comes to choices stated) do not overlap. Water can not be an exclusive choice for one person, because every living person needs water. I feel that clue 15 is simply pointless and a misdirection, because they ALL have neighbors that drink water. It might as well say he has a neighbor that wears shoes.