I was informed when I first did the Brighton gig that the cats will not drink water if they witness you filling the water bowls directly from the tap. They have to be filled from a little watering can (which you fill from the tap).
I tested this the other day. Waited till they were watching and filled their water bowls from the tap. Protests

Emptied bowls, filled can and used can to fill bowls.
All well again
