Photo by Lachy Schumacher from Burst


Waterproof phones: Waterproofing is tested and determined using 100% PURE water and protective coatings, and membranes which might be compromised by other types of water such as sea water.
This is important because the reality is that the water we encounter in our daily lives is almost certainly not actually 100% pure. Pool water may contain chlorine and fluoride. Sea water is naturally very corrosive. Even tap water may contain fluoride and other natural elements which may be harmless to us but not to your device.
Because of this, manufacturers absolutely will not cover damage by water ingress under the terms of the warranty as it is impossible to determine what the type, or purity, of the water may have been that the product was subjected to, or how long for. 
Additionally it is not always possible to determine if the user correctly closed any ports and seals - this in fact is said to be the main reason "waterproof" devices fail - and of course it should be borne in mind that these will deteriorate over time and with constant use.
As such we would always advise caution when using your phone or tablet around water, even if the manufacturer has described it as waterproof. In particular, we believe it's safer to assume your device will not be damaged when dropped in water, rather than submerged for prolonged use, but you should always ensure it is completely dried off as soon as possible, paying special attention to any ports and around moving parts such as buttons.
We do not recommend use when swimming or for underwater photography - in fact I will go so far as to say just don't do it. Industrial grade equipment specially built for use in water is extremely expensive so you're not going to achieve similar levels of protection on a device costing a few hundred pounds or less, the so please take this into consideration when purchasing.
Finally be sensible and be safe - do not attempt to charge your phone while it is in or near water, even if it supports wireless charging. Not only are you likely to damage your phone or device, it is extremely dangerous and you may lose more than just your phone. Don't let your next mistake be your last.
Jon Thompson, 1st Mobile UK.

Most popular waterproofing ratings

  • IP67: Protection against dust ingress; Protection against PURE water ingress up to 3 feet for up to 30 minutes
  • IP68: Protection against dust ingress; Protection against PURE water ingress up to 13 feet.
Period of time is usually determined by the manufacturer. Note that most manufacturers declare their phones to be water resistant, not waterproof.