An unfortunate, yet common occurrence for iPhone users is dropping their phone into the toilet or into some other puddle of water. If this happens to you, the first thing you should do is retrieve the iPhone as quickly as possible and wipe it off with antibacterial wipes, alcohol or peroxide without re-immersing it into water in order to sterilize it.
When your iPhone is cleaned, dry it as thoroughly as possible and store it in a box with dry rice for twenty four hours and then leave it sit for a couple of days. This should allow you iPhone to dry out and you can then recharge it to see if it will work. If it doesn’t work after doing that, take it to your local Apple Genius bar so they can remove and dry the battery to see if they can fix it.