She will not check to see if there is water in her bowl. Whether it is empty or full, it does not matter. She will yowl until a human being comes to the bowl an at least goes through the motions of placing it under the sink and turning the water on. It does not matter whether new water was actually placed in the bowl. She will happily drink whatever is in there after the process. She just has to see a human act like they are putting water in there before she will act like she believes there is water in there.
It is very frustrating because the human beings involved must interrupt what they are doing (which may include SLEEPING YOU STUPID EFFING CAT) or else face the threat of continuous, non-stop yowling.
My oldest cat has started doing the same damn thing this past year. I’ve been blaming it on the kidney disease and just being extra fussy with his water. Maybe your cat has started developing water-fussy behavior due to some underlying cause? It is frustrating though - doesn’t matter if it’s the middle of the night it will HAVE to be done. Not only does mine not shut up, but he’s taken to pressing against my throat if I ignore the howling - and I can’t ignore that because it cuts my air. Little bugger.
All I can offer from my personal experience is this: If you ask your vet to give your cat some pills or a shot to make it act like a normal cat, the vet will laugh at you.
In my experience, cats tend to prefer fresh water to water that has been sitting around in a bowl for a while.
The fact that she’s so easy to fool into believing the bowl has been freshly filled may indicate some level of dumbness, but I’d be inclined to think of it more along the lines of a conditioned Pavlovian-type response.
You may be able to condition your cat into stopping this behavior if you stop giving into it. Feliway spray may help. The transition would be rocky, but cats aren’t untrainable. Or you could get it one of those constantly-running fountain bowls. That might fool it into thinking the water is fresh.