Please let me share my experience before you get all excited about even remotely thinking of taking your phone for a swim or any kind of sorts ....
I am currently fighting with Samsung exactly for this reason and they have refused to honour warranty on my GALAXY S7 EDGE because they have called it "water damage".
My phone slipped out of my top pocket and fell in my 1 year old's inflatable pool which had approx. 8 inches of water in it. I immediately removed the phone after just 10-12 seconds of water immersion. I immediately wiped it , dried it with a hair dryer from a distance etc. etc. The phone was working no issues at all. After 4-5 hours I plugged it in because the battery had almost run out of juice and I get this message "moisture detected" so I turned if off and went to sleep.
Next day morning I plugged it in and it started fast charging like usual on a normal day , went to take a shower and when I came out I see the phone has a message on it that due to device overheating it has shut off apps and device was fiery hot and it wasn't charging. I unplugged and checked to find out the usb cable pin & plastic surrounding it had become deformed as if in a fire and become brown.
Bought a new SAMSUNG charger & usb cable box and the phone is working perfect EXCEPT for the fast charge which seems to have been damaged in this incident at the USB charging port.
SAMSUNG Customer Support calls this "WATER DAMAGE" on a IP68 rated water resistant phone and not covered under warranty. They say water has penetrated the internals and damaged the fast charge capability.
I am fighting with them that if you call a S7 EDGE a IP68 rated water resistant phone , how can water have gone inside and damaged ONLY fast charging capability where the phone is still working perfect without any issues ??? They are deliberately ignoring the fact that it is the outer usb port which seems to have short circuited or over heated or whatever .... Apparently the phone is not absolutely sealed or outer components not protected enough to endure water spills.
Its like paying a premium to have extra airbags in your car and then not deploying in case of an accident when you need them the most.
Found the above in SAMSUNG website for any of you that may need it !! Although I hope you don't get into this mess like I did.