Water Resistance

The definition of ´water-resistant rating´ is based on the ability of a watch case to resist the penetration of water. Some of our customers are often a little confused as to what the water-resistant rating actually means.

The water resistance of a watch is established through pressure testing carried out in laboratory settings – resembling the pressure that a swimmer or diver (when motionless) is exposed to at a certain depth. However, this does not imply that a watch - water-resistant to 3 ATM - is in fact water-resistant when diving to a depth of 30m. Instead, a water-resistant rating refers to the depth to which a watch is water-resistant at a constant pressure level. This is a common misunderstanding.

As mentioned above, the rating 3 ATM (30m) is a reference to the pressure to which a watch is exposed if lying motionless at the bottom of a 30m deep lake. When a watch is in motion at a depth of 30m, the pressure will rise to more than 3 ATM – pressure of 3 ATM is easily reached at the surface of a lake. Thus, a 3 ATM water-resistant watch should not be used for swimming or diving.

Below you will find a chart that illustrates to what degree a watch is water-resistant.

Water Resistance

NOTE: do not wear your watch while swimming if it is not equipped with a screw-down crown.

Tips for maintaining water resistance

Remember to maintain your watch regularly – especially if used during water activities. To have an authorized watch repairer replace any worn rubber gaskets as well as service and pressure test the watch - once a year or prior to any water activities - is recommended. When the battery is changed, the watch should be pressure tested (subject to an additional fee).  

Why is the term waterproof not used?

The term ´waterproof´ was deemed inappropriate many years ago as a watch can never be totally impervious to water. Thus, watches were not waterproof to a depth of 30m as manufacturers claimed – given that gaskets were not waterproof and deteriorated over time due to wear and exposure to chemicals.

Instead, the term ´water-resistant´ is used to describe a watch´s ability to resist water. If you are in possession of an old watch, you may be able to recognize the ´waterproof´ stamp on the case back. However, virtually no technical differences exist between a water-resistant watch and a waterproof watch – similar methods and techniques are utilised to protect against water. ´Waterproof´ was only used as manufacturers thought that the term was more suitable at the time.