The words “water resistant” lead many watch owners to believe, that their timepiece is completely waterproof. While a complete waterproofness is possible in principle – the tiny inscription should not falsely lead you to believe that this is the case. In the worst case this can end with a broken watch. Under high water pressure or when it is exposed to water for a long time, even a seemingly waterproof watch may let water in. How much water your watch can actually tolerate will be explained below.
The water resistance of a watch is determined using a testing procedure, which is specified under DIN-Norm 8310. According to this standard, a watch is considered watertight if it successfully passed the test in mint condition. Important to know: in this testing procedure a static pressure is applied, which allows conclusions about the bar load capacity of a watch. If you actually go under water with your watch, the pressure increases due to movement as well as a water jet (e.g. in the shower). The watch is therefore exposed to a significantly higher load than during the test, when the pressure was simulated under lab conditions.
In the table below you will find a list of different readings and associated meter data with which the watches may subsequently be labeled. Next to that it is listed what this actually means for everyday use. Therefore only timepieces from a water resistance of 10 atm (100 meters) are suitable for water sports and for diving even 20 atm are recommended. Please note, however, that this is just a guideline and not universally applicable information.