Apple certainly doesn't market its phones as being waterproof, but drop your shiny new iPhone down the toilet, and all might not be lost (apart from your dignity): one intrepid and wealthy YouTuber has found the 6s can stand a full hour of submersion.
Both the 6s and the 6s Plus sat in a bowl of water for a full hour, powered up, before being taken out and fondled extensively. The headphone and Lightning ports both still work -- probably because of the mild waterproofing applied to both -- and there's no other damage to be seen.
Obviously, this test is neither rigorous nor scientific, and you probably shouldn't go through your $US800 phone in the shower. Even if you do, powering it off and air-drying it is the best bet (not in rice, it would seem).