recover data from phone dropped in water

@binsujiro I totally agree with @jimfixer . If it does not power up and does not get recognized you cannot get your files.

I suggest you treat this just like any other water damaged iPhone. The very first thing you want to do is to clean it. Disassemble your phone using this guide. You must remove all EMI shields. If you do not remove those, you might as well not do anything. After you removed those, clean the whole board, connectors and all with +90% isopropyl alcohol. Just soaking it will not help. Follow this guide , and even so it was written for a 3G all the points are still pertinent to your phone. While you clean your board, check for any obvious damage, like burned or missing components etc. When it is properly cleaned, replace the battery. All these steps are to avoid delayed failure caused by corrosion. Best thing to do would be to clean it with an ultrasonic cleaner, but if you do not have access to one, this will at least help. Once all this is done, reassemble your phone, replace your batteryand reevaluate. Until it is cleaned, everything will only be a guess. Even with all this, water damage has only a small chance to be fully repaired, but at least you can give it a try and hope it powers up long enough to get your files off it.

The memory IC's are encrypted and paired with multiple other IC's on that particular board. Again, unless you get it to power up there is no way to access the files.