Water Resistancy

Over half of the watches currently on the market worldwide are labelled as water resistant. Unfortunately this is not very helpful to the average person who is shopping for a luxurious timepiece as it does not reveal any important information. Water resistant is used as a generic term in horology and can mean anything from a watch that is simply splash proof (for instance in this case water resistant means if you splash your watch whilst washing your hands it will not be damaged) or it can mean pressure tested and capable of being worn by divers (in this case water resistant means that it has been tested to a great depth and is resistant not only to water but also to great pressure). The water resistant mark is always applied to the case back or dial of watches that are water resistant and they will indicate how well it is sealed and to what depth it is safe.

Confusingly many different units are used to indicate the depth that your timepiece is water resistant to, the most common are meters, feet and bars. Meters and feet are self explanatory, once your watch gets down to the depth that the watch is described as being safe to (often referred to as the test depth) then it will very probably succumb to the water pressure and allow water to ingress into the watch, damaging the inner workings and mechanisms. Bar is a measure of pressure and has a direct equivalent in meters, so if you see a watch that is advertised as being water resistant to 5 bar then it is safe down to 50m, 10 bar is equivalent to 100m, 20 bar is safe down to 200m and 100 bar is right down to 1000m.

You should bear in mind that whilst these depths and pressures are given and the manufacturer often promises that the watch is safe down to these depths the measure of a water resistant watch refers to the maximum safe depth for the timepiece as a test depth with good reason; with the variation between watches (particularly hand made watches) your watch may not be safe for long at this depth or may not even make it down to this depth at all without springing a leak or becoming damaged. Water resistant does not mean that you can use the watch for any length of time at depth; if you are planning on doing so then you should invest in a certified divers watch that will feature a more robust construction and is tested to far greater depths and pressures than a standard watch. For instance many watch manufacturers will recommend that a watch tested to 5 bar (50m) should only actually be considered water resistant for jobs such as washing your hands or taking a shower. A watch tested to 10 bar (100m) is recommended to be worn only for swimming on the surface of the water, whilst a watch tested to 20 bar (200m) should only be used for shallow SCUBA diving. ISO 2281 is the international standard that defines a watch as water resistant and it should never be confused with ISO 6425 which confirms as watch is properly resistant to fluids and pressure and is safe for diving to any depth with (ISO 6425 watches will be marked as "divers" and not "water resistant").