I'm pretty sure the water in a vodka bottle is illegal in most places in the US unless you at least cover the labels. Even if it isn't, you are probably going to get a bit more attention from the police than you want.
It probably isn't, but appearances are everything. You will get the attention of the police, who probably will not believe you. They will still try to give you a ticket for public intoxication, they will search you, it will be a hassle. You will probably get some kind of fine, even assuming you can prove it is water. You may go to court. Bottom line: not worth it.
(I think I'm doing it right)