Apple claims that its iPhone devices come with IP ratings that make them resistant to splash, water, and dust as they are tested under controlled laboratory conditions. It doesn’t mean that all iPhones are completely waterproof.
They remain protected in water only up to a certain period of time and depth, but in an unexpected event, an iPhone that was retrieved after a year in a lake was found fully
functional.
The Four Lakes Scuba Club in Madison, Wisconsin, fished out iPhone when it took up cleanup operations in Lake Mendota. In general, the club comes across several phones during their regular cleaning process of the lake, but most of the phones do not work when the club members try to charge them.
But an iPhone they found in the lake recently took them by surprise as the screen of the phone lit up when the phone was charged.