According to Samsung, the phone will be fine on water submersion in fresh water IP to a maximum depth of 1.5m up to 30 minutes.
I'm sure the phone will be fine, but really it's just at your own risk.
I've had no problems with water and a time or two it's been completely submerged for short underwater video. Just be sure your battery has plenty of juice because the USB port will be disabled as long as it senses moisture. Once dry it will return to normal operation.
(Also the touch screen will react to the water droplets running down it and can become annoying)
I thought the same thing but after shopping for a case equivalent to a LifeProof and not finding anything just took the plunge and continue to use in wet environments