YouTueb channel EverythingApplePRo has posted a video to demonstrate how the new iPhone 7, which has been called "water resistant," would far in an extreme deep water test. The video, entitled "How Deep Before it Dies?" shows the iPhone 7 and a Samsung Galaxy S7 being lowered into deeper and deeper waters.
Apple's iPhone 7 series is certified to IP67 standard water resistance, which means the handsets are built to withstand being submerged in up to 1 meter (about 3.28 feet) of water for half an hour at most. Samsung's handset carries the higher IP68 certification, indicating it can withstand continuous immersion in over 1 meter (3.28 feet) depths, or up to five feet, according to Samsung.
The first test dropped the devices 5 feet, already exceeding the iPhone's capabilities. Both devices worked fine. They then continue to increase the depth by 5 feet intervals. At 20 feet, there were no signs of damage so the tester added another 10 feet. At 30 feet for five minutes, the Galaxy started to reboot sporadically and the iPhone's Taptic Engine-based home button started to malfunction.
At 35 feet, the Galaxy's display won't come on, but the iPhone 7 holds up despite some water damage.
This is typical for Apple's waterproofing - they will tell you it only works so far, but it will go down much further with some damage. While you shouldn't go underwater swimming with your iPhone, you don't have to worry so much about it dropping into the toilet.
See for yourself: