Water Resistance

Watch Resistance

Water Resistance:

A watch rated as Water Resistant may come in contact with water to a predetermined extent. Most watches are classified by the degree until which depth of immersion is safe. It is important to remember that a water resistant rating is based upon optimum conditions in a laboratory. Real life experience and aging of the gaskets will effectively decrease the manufacturer's specifications of water resistance over time. Water coming in contact with the movement is the worst scenario that can happen to a watch. Thus, it is strongly recommended that you always work well within the parameters of the manufacturer's recommendations and have your watch tested at least once a year. Any competent watchmaker has the necessary equipment to test water resistance.

The U.S. FTC (Federal Trade Commission) which enforces the truth-of-advertising has deemed the term "Waterproof" inappropriate. In their opinion, a watch can never be 100% truly impervious to water, as the gaskets deteriorate over time and exposure, thus reducing the specified depth of water resistance. In the words of the FTC "The word proof connotes a measure of absolute protection that unfortunately does not exist with respect to watches, especially over prolonged periods of time." The FTC has found the term Water Resistant to be more appropriate.

Water Resistance Testing Methods:

Dry Test: The watch is placed in a chamber and the air-pressure is increased. The machine detects the smallest variation in the case size. If the case expands, even slightly, then the watch is not water resistant.

Wet Test: the watch is placed in a chamber which is half filled with water and half air. Air pressure is increased while the watch is out of the water, then the watch is slowly immersed into the water. Once the watch is completely immersed, the air pressure is slowly released. If bubbles come out of the watch it means that air seeped into the watch prior to immersion AND the watch is not water resistant. This method is generally used as a second test to pin-point the problem area.


ATM is short for "Atmosphere" which is equal to 10 meters. Another word for ATM which is commonly used in Europe is BAR - this too is equal to 10 meters.

Interpretation of the Depth Ratings:

Although a watch may be rated 30m/99ft water resistant, it does NOT mean that the watch can be immersed to that depth. The depth rating posted by the manufacturer is theoretical in nature and can only be achieved in a perfectly optimum environment of a laboratory - which is impossible to replicate in real life.


No Rating - 30m/99ft

  • Does not allow contact with water

30m/99ft - 50m/165ft

  • Contact with water such as washing hands and rain

50m/165ft - 100m/330ft

  • Light poolside swimming

100m/330ft - 200m/660ft

  • Swimming, snorkeling, showering (no hot water)

200m/660ft - 500m/1650ft

  • Impact water sports such as board diving and scuba diving


  • Appropriate for serious deep water diving.


  • Have your watch water-tested once a year.
  • Do not shower or swim with your watch unless it is rated 100m/330ft and has a screw-down crown.
  • Never open, wind or operate the crown while in water.
  • Never press the buttons of a chronograph watch while in water, unless otherwise stated by the manufacturer.
  • Do not subject your watch to extreme temperature changes.
  • Do not subject your watch to sudden and rapid air-pressure changes.
  • Do not allow your watch to come in contact with corrosive chemicals, such as abrasive soaps and highly chlorinated water.
  • Ensure that the crown is always pushed in, and if you have a screw-down crown, make sure it is always tightened. Double-check before immersing in water.