The iPhone 6S is a win for water resistence
Jeff at iFixit:
We had our suspicions, based in part on Apple patent filings in one particular area: waterproofing. Apple has been investigating a waterproof (or, more accurately, liquid proof) iPhone for at least the last several years. If that strip of sticky goop on the 6s wasn’t put there to hold the display in, then maybe—just maybe—it was designed to keep liquids out. Like a gasket!
Of course, that was only a theory. But over the weekend some brave Apple fans introduced their new iPhones to a life aquatic. The phones didn’t always emerge unscathed, but the overall trend is clear: the 6s and 6s Plus are dramatically less prone to liquid damage than their predecessors. (They aren’t, of course, completely waterproof—so don’t jump into a pool with them or anything.)