The water charge is based on size of the unit and number of occupants..  They give you the whole breakdown when you sign a lease in North.

They didn't give us a break down when we moved in, but I just got my second bill for another three months and it was only $14.15.

I moved in at the very end of August and my first bill water was around $14 and just got my second for $9.97, so not bad.  I am in a studio so I would expect in the larger apartments/more occupants it is more.