There's a problem with your assertion.

Even if we go the the barest assertion that the definition of "wet" is "being covered in, or saturated, with water" ... Unless you're specifically talking about a singular water molecule (and have fun collecting just one,), water is in fact also covered in, or saturated with, water.

That is to say, water is in fact wet.

Which, is probably why Webster's defines "wet" as:

consisting of, containing, covered with, or soaked with liquid (such as water)