In the last place we rented we apparently had to pay the water bill at the end of our lease when we were moving out. The night before hand over of keys we were looking through the lease and discovered that on the last page it said we were to pay the water bill. We freaked out cause we had obviously overlooked this and we had no idea how much it would be.
When I was handing in the keys I mentioned it to the receptionist and she checked for me. She said normally we would have to pay and it would be taken out of our bond !! But since we had done alot of work for the land lords they were waiving the bill (3 years worth of water bill)

We were lucky in this case but we could easily have been caught out and left with next to no bond (I dont know how much the bills added up to)

Good luck getting it sorted !