It's rated IP67, which is water RESISTANT to 1 meter for 30 minutes, so I'd want to see the written warranty that covers water damage before I'd call it waterproof. There's currently no specification for completely waterproof, except for IPx8, which means the manufacturer specifies the conditions, so some manufacturer could specify 100 meters for an hour, or water can get in but the circuitry is protected if it gets wet, or something like that.
The last phone I know of that was waterproof to a decent depth (I dove to 20 feet of ocean with it a few times, just to have a timer with me, and it still worked after an hour) was the Nextel i700. (I don't know if it was atom bomb proof, but we used to throw it hard against the floor of the store to demonstrate what it would take. [The battery cover popped off and the battery fell out.])
There are probably military phones that are "everything but blow it up-, or put a bullet in it-proof", but I don't know of a single civilian phone that the manufacturer guarantees against water damage. (They're working on it, though - coating everything inside, so that if water gets in, only the coating gets wet and the phone still works.)