The Water Tower is a tower that is in East Citadel. It contains watermelon juice, hence its name. In "Table Soccer Competition", whoever lost the competition was required by the terms of the competition drink all its watermelon juice. High Roller lost, so he had to drink all the juice, which bloated him.
The Water Tower is a tall tower with wooden legs. The tank which contains all the juice is shaped like a big watermelon with a cork in it and a tube coming off of it.