Is my watch waterproof?

Watches often have a very confusing indication of water resistance.

Because with a "50 meter water-resistant watch" you can't just dive 50 meters deep.

How does the test process work?

Let's take a watch with a rating of 200 meters as an example:

To do this, a watch has to withstand a pressure of the equivalent of 20 bar for one hour , and then another hour at a 25% higher pressure (25 bar = 250 meters).

-However, the watch is placed motionless in a water column-

When jumping into the water and swimming , a higher water pressure than the guaranteed pressure can build up on the seals for a short time. Watches that are significantly cooled down after prolonged sunbathing, for example by jumping into water, are particularly at risk.

That means: 

A watch that is water-resistant to 50 meters cannot simply be used for diving

-The rule here is that static pressure in the test procedure is not the same as dynamic pressure when wearing a watch-

In addition, a watch is only waterproof at the time of testing. However, this can change at any time due to classic ageing, wear and tear and damage.

The seals age and become brittle over time.

Strong temperature fluctuations, sweat, but also sunscreen can accelerate this. Impacts on the crown, for example, can also lead to a loss of water resistance.