When it comes to water, cats are very unpredictable creatures. You just don’t know what they will do; each feline being very different from another, some are even known to like swim or be bathed.
More commonly, however cats dipping their paws in water, they might be trying to make the water move. Cats prefer to drink from flowing water, which tends to be purer than water which has been sitting around stagnant for a long time and has built up germs. Most water sources in nature embrace moving water, such as rivers and lakes. Even in the comfort of their own home, cats seem to prefer to drink running water from faucets and bathtubs.
Cats view their food to be their territory and what they think is theirs, they will mark as such. They may put their paws in water in order to claim their property. Sometimes, cats drop their toys in their food and water bowls because they like to keep their belongings together. Cats hardly ever leave their possessions in areas that they are not recognizable with or do not consider their own.
The eyesight of a cat is not keen when seeing things up close such as the surface of water. Since cats truly detest getting their nose or whiskers wet, they may test-dip their paws in the water to be able to tell how deep the water is... Once they know the depth of the water, they can sip it without having a mishap, such as getting unpleasantly wet. Fur takes a long time to dry.
Cats may not like the taste of the water that is dormant. When they put their paws in, they may be trying to stir up the water to make better the taste. Like children often do, they may be kittenishly playing with water because they do not want to drink it just now.