I honestly hadn't even thought of whether there are issues. I've not seen a single official do it (go to the bench for water) in basketball here, and I'm not interested in being "that guy."
Pssst, did you see that snaqs guy? He was near a Gatorade thermos at the end of the bench and actually sipped some water. I'm tellin' ya, I saw him do it. Ohh, I saw it!