You know that cats should always have a supply of water, especially if you are feeding them dried food. There on your nice clean kitchen floor is a bowl of nice clean fresh water, in a nice clean bowl.
What does your cat do? Maybe gives the bowl a sniff and walks away from it, or just ignores the bowl completely, as if water were the last thing a self respecting cat would consider drinking.
"Okay", you think to yourself, "Kitty just isn't thirsty at the moment". But then later, you happen to spy your cat busily lapping up stale water from a puddle in your garden as if it was nectar.
Cats are self-reliant, independent creatures, but surely your cat is not going to turn its nose up at the nice clean water you provide, just to let you know it can survive without you? After all, kitty does not reject the food you provide even though it is perfectly capable of catching mice.
No, the answer is not your mouser's independence. Tap water is usually treated with chemicals, often chlorinated strongly enough for a cat to smell it. Cats noses are far more sensitive than human noses and many cats find this chemical odor very offensive. Stale water in puddles and pools has a far more attractive smell are far as a cat is concerned. Puddles may be full of rotten vegetation and microbes, but cats find this organic soup very tasty.
As well as the off-putting odor of chemicals in tap water, cats find the smell of detergents repugnant. So, because you diligently clean your cat's water bowl in the interest of hygiene, the detergent that you use deters your cat from drinking from it. You use the same detergent to wash your cat's food bowl, why then, does your feline friend eat heartily from the bowl, and not be repelled by the smell of the detergent? This is because the aroma of the fish or meat is stronger than the smell of the detergent.
With the water bowl, the combination of the two unpleasant smells, the chemicals in the tap water and the detergent, means that your cat will only quench its thirst from the water bowl if there is no better smelling option to be had.
So, what can you do? You need to rinse your cat's bowl more thoroughly than you would a plate for a human. Remember feline noses are far more sensitive than ours, every trace of detergent needs to be rinsed off. Secondly, let the water from the tap stand for a while before putting the bowl down for your cat, this will allow the chemicals to dissipate.
These two things should have kitty drinking happily from the dish, unless, of course, kitty has got so used to drinking from puddles it just can't kick the organic water habit!