Water Damage Checker

In certain models of iPhones, there is a special indicator in the SIM Card slot that will indicate how severe water damage is. Just open the SIM Card slot (on the side of most iPhones) and shine a light into the port. If you see red, purple, or blue, there is severe, moderate, or light water damage respectively. If you don't, either there's no water damage or your iPhone isn't equipped with one.