Cats were originally desert animals, so they don’t need quite as much water as you might expect. That said, they do need to drink water regularly. If they tend not to, dehydration is a legitimate concern.
Try putting out a water bowl that’s wide enough for your cat to drink out of without his or her whiskers hitting the sides. If your cat prefers running water, a cat water fountain may do the trick. Either way, always make sure your cat has access to fresh water. You could also include wet food in your cat’s diet to subtly increase moisture intake.