Interestingly, Apple’s warranty for the iPhone 7 and 7 Plus does not cover liquid damage. So warranty service company SquareTrade decided to put the iPhone 7 through a water test. When SquareTrade submerged the iPhone 7 in one meter of water for 30 minutes, it survived with temporary audio muffling. Temporary audio muffling is common for IP67 and IP68 devices that have been used in showers and baths. 
EverythingApplePro conducted a more specific water depth test for the iPhone 7 against the Samsung Galaxy S7 (IP68) by sinking it at different increments. In the first test, the iPhone 7 was submerged five feet in the Columbia River for five minutes. Fortunately, none of the devices were damaged in that test. After 5 minutes in 10 feet, 20 feet and 30 feet of water, both devices survived without moisture in any of the cameras. When the Galaxy S7 and iPhone 7 devices were submerged 35 feet deep, the iPhone 7 continued to work -- but the Galaxy S7 stopped working: