G.U.R.(
Ground Under Repair in a golfing context) does not exist within the boundaries of a hazard. To get relief, you must take the penalty associated with hitting the ball in a hazard, unless you are in a
bunker, in which case you much play the ball as it lies. The exception to this is
casual water, which does not exist in a
water hazard, but does exist in a bunker. In which case you must drop the ball at the nearest point of relief no closer to the hole while keeping the ball in the bunker. Or, you can take a one stroke penalty and remove the ball from the bunker and drop it within one
club length no closer to the
hole.
Refer to sunpigs' write-up for the correct procedure on taking relief from GUR.
Also, remember that you can always play the ball as it lies(with the exception of out of bounds and a nature reserve).