My sister was in Hawaii on vacation. While at the beach a crab startled her and she dropped her iPhone 6 in the water. She quickly retrieved it and put it in a bag of rice to absorb the water. She wanted to get the pictures off the phone and gave it to me to try an fix it.
I opened the phone and found corrosion by the Home button and the connection going up to the logic board. The phone would not power on or charge. I disconnected the corroded ribbon cable from the Home button and plugged it in and the screen came on showing a dead battery. At that point I knew the phone should be repairable. I ordered the two parts and replaced them with no trouble. The phone works great and the pictures were downloaded.
The biggest thing that kills wet electronics is the battery. The battery power with the water will dissolve connections and short things out. If you get some electronic device wet, remove the battery as soon as possible. Usually clean water wont do damage things, salt water is another thing.