I would HIGHLY recommend buying a bottle of distilled water, taking the battery out and agitating the phone in that for a few minutes. Then take it out and dry it off with a hair dryer on medium/low heat. Finally fill a tupperware container with dry rice and leave the phone to sit in that for 3-4 days.
Water is not the enemy, the minerals in hard water are (if you would have been lucky enough to drop your phone in distilled water you wouldn't have a problem)
. When hard water dries it leaves behind minerals that will corrode your electronics. Your phone may work right now but minerals will keep corroding it. Dipping and agitating in distilled water will absorb most of those minerals and then sealing it in tupperware with rice will suck out any remaining water.