The question is imprecise. It should be: “Why do domestic cats generally dislike being submerged in water?” Obviously, cats like to drink water and therefore they like water if they are drinking it! And the word “cats” includes all cats; domestic and wild. There are many wild cats (and some domestic cats) who like to be in water for short or long periods of time such as the Bengal tiger on a hot day. And there is also the fishing cat which spends a lot of time in water. As does the flat-headed cat. But this question is about domestic cats hating it when they are submerged in water.
You will see various answers to the question. There’s no hard science on this so the answers are anecdotal. My answer is this: the main reason domestic cats don’t like being submerged in water is because it removes their natural scent from that fur and skin and they need to reapply it by grooming themselves. In other words, it is unnatural for a domestic cat to be submerged in water when bathed. They don’t need to do it to keep clean. If it’s unnatural and they have to do work after they’ve been submerged in water, they will normally avoid it.
That said, domestic cats are good swimmers and sometimes they have to swim to survive. And indeed, some domestic cats end up enjoying swimming in the sea for example with their companion. I’ve seen videos of those activities. So, we can’t say that universally all domestic cats hate being submerged in water. But in general, they won’t like it.
2. Ancestral inheritance
The back story to the domestic cat is also an underlying reason, by which I mean that the domestic cat’s wild cat ancestor, the North African wildcat, lives in a very dry part of the world and therefore is naturally habituated to dry conditions and is probably unfamiliar with living and hunting within watercourses. Although, there must be occasions when this wildcat does indeed stalk prey in a watery environment. So, this ancestral reason is a weak one, I think.
Another possible underlying reason is that tap water in developed countries is treated with a low level of chlorine to help prevent micro-microbial contamination. I think this applies under the law in the USA. The concentration is very low in England and Wales at 0.5 mg/L or less. But we know how sensitive the noses of domestic cats are and therefore even this very low level of chlorine will be detected by them (reason why cats prefer rain water). This chemical will remain on their fur when they come out of being submerged in water and they will smell it. They won’t like it, in my opinion. They only want their smell to be on them. The smell of a cat is an identification signal for that cat.
4. Identification issues when scent washed off
I’ve mentioned this before but if two cats are very friendly with each other and one cat is submerged in water and dried off it is likely that the other cat will no longer recognise them or be confused when trying to identify them. They may hiss at this unknown stranger until their scent has been reapplied. That is the power of scent to the domestic cat as a form of identification. Cats don’t want to lose that identification. It is part of their psyche.
5. Wet, heavy coat and discomfort
Another possibility is that when a fur coat becomes wet it becomes much heavier and this won’t feel particularly nice to a domestic cat. The feeling that they have after being submerged in water will be mild uncomfortableness. They will want to get back to normal. Knowing that beforehand (and I think they do know that beforehand) they will want to avoid being submerged in water.
I have to make one last point which is about cats being outside in the rain. A lot of cats don’t like being in the rain for the reasons mentioned above about being submerged in water. The same outcome applies to heavy rain. But quite a lot of cats don’t mind being in rain. However, their guard hairs, the ones on the outside of their coat, protect their undercoat and they don’t get sopping wet as if they’ve been dunked in water. They might barely feel the rain on their back as a consequence. Although a cat that has been caught in a rainstorm will no doubt groom themselves when they come inside.
Wild cat hybrids
Postscript: you will find, I believe, that the high filial wildcat hybrids are much more likely to enjoy getting wet or are more accepting of it because they have this strong connection with the wildcat. For example, the Savannah cat has serval DNA in them and the serval will often hunt near water in long grasses. This is going to come out in the behaviour of an F1 Savannah cat for instance. The point being that you can’t generalise about domestic cats hating water and you can’t stereotype them as to hating water.
BELOW ARE SOME MORE ARTICLES ON WATER AND CATS.