i Can't stand posts when someone asking someone to connect water damaged phone to any kind of voltage...
After Water Damage, You have to turn off Your phone, do not try to charge or any factory reset. Only thing what you do is bring Your iPhone to any kind of service, which have an ultrasonic bath, and after the process of cleaning logic board with IPA, and ofcorse drying Logic Board, you can try to turn it ON
iPhone IS NOT WATERPROOF in that sense what people thing, it's only commercial.