SWKTU

An indication of the test pressure in terms of water depth - meters - DOES NOT MEAN a water-resistant watch was designed for repeated long-term use in such water depths.

 

For example, a watch marked 30 metres (3 ATM) water resistant can not be expected to withstand activity for longer time periods in a swimming pool, let alone continue to function at 30 metres under water. It is even not safe to take a shower with such a watch!

 

This is because the test is conducted only once using static pressure on a sample of newly manufactured watches.

 

The test for qualifying a diving watch for repeated usage in a given depth includes safety margins to take factors into account like aging of the seals, the properties of water and seawater, rapidly changing water pressure and temperature, as well as dynamic mechanical stresses encountered by a watch. Also every diving watch has to be tested for water resistance or water-tightness and resistance at a water overpressure as it is officially defined.