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Diving deeper

30 m, 3 bar or 3 atm — which unit of measurement correctly expresses the water-resistance of watch? What does “water-resistant” mean? And if you’re wearing a watch that is water-resistant to a depth of ten meters, can you really dive ten meters down with it? We’d like to bring some order into this multiplicity of terms, and we’ve also put together a number of tips for you. Here you can find out more about how to handle a watch perfectly if it comes into contact with water.

Graphic test pressure and water depth


Depending on the manufacturer, the water-resistance of a watch is expressed in bar (bar), meters (m) or atmospheres (atm). Meter indications cannot be equated with the depth of a dive. They do not refer to the depth of a real dive, but rather to the water pressure during a test under laboratory conditions. The term “1 bar” normally corresponds to 1 atm, or the pressure at a depth of ten meters under laboratory conditions. Watches with a water-resistance of 1 bar are protected from splashes. Nonetheless, you should not wear your watch while showering, swimming or diving.


Water pressure increases quickly and at very different rates. For example, in daily use the pressure on a watch increases if it’s held under a stream of water (up to 4 bar) or worn while the wearer is swimming, jumping from the edge of a swimming pool or being swept off a surfboard.


Wempe waterresistant icon


Water-resistance is not a permanent quality. Watch seals age at different rates, depending on how the watch is worn and what it is used for. In addition, sealing elements are attacked by sweat and acids, and they deteriorate over time. If a watch is exposed to big changes of temperature — for example, if the wearer takes a sunbath and then jumps into the water — condensation may form inside the case. Saltwater also causes increased corrosion. That’s why a watch should be rinsed in freshwater after a dip in the ocean. We basically recommend having the seals and the water-resistance of a watch checked once a year. We perform this service for our customers free of charge.
Graphic Acid, saltwater and temperature


Two DIN standards have been established to clarify the term “water-resistant.” The DIN 8310 standard defines the water-resistance of small watches. Watches that are designated “water-resistant” must be resistant to sweat, rain, and being dipped into water for more than 30 minutes at a depth of one meter. If a watch remains watertight under these conditions, it may legitimately be designated “water-resistant.” Watches in this category can be worn while washing one’s hands, but not while diving.



The DIN 8306 standard imposes many different requirements on a professional diver’s watch. Here are a few examples:


  • The watch must be capable of remaining watertight for two hours at a depth that corresponds to the water pressure specified by the manufacturer. This must be followed by a three-hour stay at a depth of three meters.
  • The diver’s watch must be able to withstand 24 hours in warm saltwater without showing any visible traces. Alternatively, it must continue to function during and after a 20-minute stay at a depth that corresponds to the water pressure specified by the manufacturer.
  • The watch must have a device for selecting a specific period of time; usually this is a ring or bezel that can be turned in one direction. The selected period of time and the second hand must be visible even in the dark.
  •  Before and after every pressure test there is a condensation test in order to determine whether the case is watertight. The watch is warmed up to a temperature of 40°C, and the crystal is then sprayed with a drop of water. After the watch is wiped dry, there should not be any condensation on the inside of the crystal.


A guide: An overview of water resistance
  • 3 bar: The watch is protected from splashes. You can wash your hands while wearing the watch.
  • 5 bar: You can wash your hands, shower or bathe while wearing the watch.
  • 10 bar: You can swim, snorkel, do water sports or ski while wearing the watch.
  • 20 bar and above: These are diver’s watches for scuba diving.
  • Over 100 bar: These special diver’s watches are made for deep-sea diving.

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