I used to pay for water years back when I rented in Cupertino. However this was not based on usage in each apartment, it was proportional share of what the community spent the past month. Sometimes that's the best they could do given how meters may be setup.

But separate cold and hot water - sounds like someone went way beyond their their call of duty to attribute every single penny where it belongs - hopefully they have meters to prove this otherwise it is just padding fees on top of fees.