Wow, there were so many great suggestions for that kitty who just wouldn't drink! We can all agree that it's an important problem that should be addressed pronto, and I'd like to give a special thank you to TsuKata for offering this tip from the vet who shared it with her after she had a cat that refused water. She writes:

Grab at the kitty's loose skin a little, not a pinch, just a gentle grasp that moves the skin up. It should be almost like you're scruffing her but not so much that you're lifting the kitty and not necessarily at the scruff. See if the skin has elasticity and goes back to the body immediately when you release. If it does not, your cat is dehydrated and should be taken to a vet to be given fluids immediately. If it does go back quickly, even though the kitty hasn't theoretically had water two weeks, your cat is likely drinking from a sink, toilet, or other source . . . and you just need to find that source.