LG G3 is one of the simplest and finest smartphone of this year. Officially G3 is not water resistant, but an risky experiment shows that it is also water resistant like other flagships as Galaxy S5 and Xperia Z2.
After the test the phone worked quite well. Speakers, Microphone, NFC worked as usual. There was a little problem with the camera. Though water entered through the USB charging port, it too worked well. LG seems to be going by work not by words and publicity. So G3 owners, use it underwater there is nothing to worry about.