Amongst all the chatter about the Google Pixel phones, one popular topic of discussion was Google's decision not to make the Pixel phones totally waterproof. While they do carry an immersion rating of IP-53, the certification doesn't guarantee any kind of full submersion. Rather, the IP-53 rating only covers sprays and splashes that come in contact with the phone up to 60 degrees from the top. Meaning you'll be fine if you're caught in a rain storm while actively talking on the phone. So why are other phones like the Samsung Galaxy S7 and the iPhone 7 fully submergible while...
Source: http://www.gsmarena.com/google_wasnt_able_to_make_the_pixels_waterproof_due_to_time_crunch-news-21270.php