welcome! anything urgent? 
I know exactly what you're talking about. The water bottle does indeed stop working suddenly, but I have decided to lay out a bowl of water for him. He has drunk from it before, so I know he's ok using a bowl.It isn't uncommon to miss rats drinking so I wouldn't worry too much if u don't see it.
But it is a good idea to double check that the bottle is indeed working. Often they can be annoying