Water cats in this context means cats that like water. Yes, some cats actively like water. That applies to some wild cat species, domestic cat breeds and many individual cats. It is simply not the case that cats hate water; that is far from the truth.
A lot of wild cats live next to water courses because prey is more abundant prey there. And a good number of domestic cats, usually wildcat hybrids like water. For example, Kathrin Stucki of A1 Savannahs says that her Savannah cats like to join family members in the shower etc. That said your typical domestic cat generally does not have much of an affinity for water.
The domestic cats that come immediately to mind that like water are the Savannah and Bengal, both wildcat hybrids and, of course, the Turkish Van(known to be a good swimmer, the experts say) to name just three. The Turkish Van comes from the lake Van area of Turkey. Did it learn to swim in the lake?
Tigers often spend large parts of the day in water, half submerged, to keep cool. The tiger is a remarkably strong and competent swimmer (and all round athlete). It has been recorded swimming to islands in the Sunda Straight (between the Indonesian islands of Java and Sumatra). This is open sea and considerable distances are travelled.
The fishing cat, as the name implies, is at home in the water and can swim for long distances in water and under water. They keep their head above water when swimming and propel themslves forward doggy paddle style. The fishing cat catches fish as well as animals on land. They are true water cats.
The jaguar is associated with water courses and streams in a wide range of habitats. They are excellent swimmers and have been recorded swimming across wide rivers. They also like to spend time in the water half submerged when it is hot.
Jaguarudis love water (ref: Hand-raising jaguarundis (puma yagouaroundi) by Buzas and Guylas FCF magazine vol 56, issue 2). Observed to love to be in water from aged 5 weeks. Played in drinking bowl. Defecated in bowl.
Apparently, there are (or were) rumors that leopards don’t like water to the point of not getting their feet wet. This is incorrect as they are good swimmers and enjoy the water. They are very adaptable cats and what is called “generalists” meaning they can cope with a wide range of environments and don’t mind what they eat.
The Asian leopard cat is the wild parent of the Bengal cat and I have already said that Bengal cats like water so it is no surprise that the leopard cat likes it too, even moreso. In fact, they are excellent swimmers and have an affinity for water and an ease in it (many a Bengal cat keeper will attest that). Captive leopard cats can be seen to spend a considerable amount of time playing in water.
We don’t really think of a lion swimming across rivers. We normally see them on pretty arid and hot plains. Yet the lion is a capable swimmer and they have been observed swimming across large rivers.
Finally, the flat-headed cat is a fishing type cat like the fishing cat. A large part of its diet is composed of fish. The distribution of the flat-headed cat linked to water.
From Water Cats to Wild Cat Species — Sources: YouTube, Wild Cats Of The World (Sunquists) and PoC.