I'm firmly on the side of "water is not wet" in this debate, but it's a question that I was asked while I was high and have no answer to it. Water cannot itself be wet because you can't get water on water. However, what is a fish in a lake? It can't be wet until it's taken out of the water, but it's not dry either. Is it something else?
I've never seen a sponge sink on its own, so in some sense they will always either wet or dry when not in use. If something holds a sponge under water, it becomes immersed and gains this mysterious new property