I don't know if there's anything you can do unless you catch her in the act. Yes, squirting her with water isn't going to work, silly kitty. Maybe the pennies-in-a-can trick that people use with some dogs would work. take some coins or small pebbles and put them in an empty Coke or other soda pop can, and tape over the opeing. When you catch her in the act, shake the can - it makes a loud, unpleasant noise that she won't want to hear again.

Of course, the other alternative is buying a cheap waterproof placemat to put under her water dish, so that when she does it, the floor doesn't get ruined!