|"I don't like it when it's on tap"|
Cats are not intelligent the same way humans are, but they seem to have feelings and personality and preferences. Michelle (the largest, colored like a milk cow) likes to drink water from the sink. She'll come right up to you, stare at you until you follow her to the bathroom, and wait for you to turn the tap on.
Imp, on the other hand, either hasn't figure out the sink-drinking thing, or just doesn't care for it. Just now she carefully followed me to the bathroom and looked like she wanted the water turn on, just like Michelle. Then she looked the whole thing over carefully, as if pondering what it all meant, and then walked away. I know she knows it's water, but she is just not interested in that sort of drink.