Why does my cat keep knocking over the water dish? How to stop it?

There are several reasons cats like to "knock over water dishes" or play in their water bowls, including (1) it's fun - they enjoy splashing the water and making it move, seeing the reflective surface, (2) they prefer to drink from a moving water source (because moving water is more aerated and generally tastes better/fresher), (3) the bowl isn't to their liking - too big, too small, too deep, etc., so they splash water out and drink from the floor, (4) you give them fresh water whenever they knock the dish over so they have learned that this a successful method of getting your attention. Some things you can do include: (1) purchase a water fountain for cats (water moves continuosly); (2) get a heavy cermic bowl or a bowl with a wider base than top, (3) put a placement or plastic tray under the bowl, (4) offer more shiny, sparkly toys, like Mylar balls, to catch your cat's attention, (5) changed the water at least twice per day so your cat doesn't need to ask you for clean water.