At face value, this obsession makes no sense. Cartoons, after all, have spent many decades teaching us that cats hate water. So what's the deal?
Some cats prefer to drink water that's moving.
Many cats like to drink running water. Some will only drink from water that's moving, to the great annoyance of their owners. Why is this?
The answer probably lies in survival instincts. Cats tend to seek out fresh, clean water over stagnant water, probably because fresh water is less likely to contain harmful bacteria than stagnant water is.
Cats also don't need very much water. They descended from desert dwelling animals, and they take in much of their necessary water from their food. So, more than other domestic animals, cats can afford to be pickier about where they get their water from.
Plus, running or moving water is just fun, which brings us to our next point.
It's common for cats to paw and play with water.
Does your cat paw at their water dish? Many cats do. We don't know for sure why, but there are a couple of possible explanations.
Checking it out: Does your cat tend to paw at the water dish and then, ultimately, start drinking? Interestingly, they might be checking the water level before diving in. Since the bowl's water level varies throughout the day, as well as from one day to the next, your cat might just be gauging how high the water is. Some cats find it uncomfortable to get their faces wet, so they don't want to shove their face into a water bowl that's filled to the brim.
Playing: Let's face it: water is a fun toy. Cats love anything that moves, and water is very good at moving. Your cat might enjoy batting at running water from the faucet because it's shiny and reflective, and because it moves quickly, much like their favorite toys do. And though they probably don't enjoy being submerged in water, the feeling of running water against their paw might be surprising and interesting, prompting them to do it again and again.
If your cat is obsessed with running water, they'll probably enjoy a cat fountain. Cat fountains are stimulating, and also encourage your cat to drink more. Plus, they can save you from constantly cleaning up spilled water.