Watch Education Water Resistance Guide

Most watches are considered water resistant, meaning that they will withstand some splashes or rain.  Water resistant does not mean that you should shower or go swimming with the watch on.  If you wanted to wear your watch swimming, look for depth resistance.

Different brands will rate depth gauge as either BAR, ATM, meters or feet.  This means that the watches have been tested in a laboratory withstanding a static pressure for a short period at the stated depth.  The actual water pressure when in use outside of the laboratory is typically greater than the tests.

Breitling and Panerai Dive Watches

Important Factors

Remember to ensure that the crown and buttons are returned to their normal positions, these are the most important factors for maintaining a dry watch.  If you have any screw down buttons, be sure to tightly screw them back into place.  The crown-stem hole is constantly being moved when winding and setting the time, so ensuring that there is a good seal with help keep water from penetrating your watch.

When the crown is “unlocked” the watch will lose its water resistance and can either slowly leak or completely flood.  In addition to ensuring the crown is secure, it is a good idea to give the case back an inspection before submerging the watch.  This step is especially important to snap on case backs as they are considered the least water resistant and should not be immersed in water.  These backs can be damaged easily causing a weak seal and water leaking in.

Case backs that are attached with screws add the next level of water resistance.  This allows for a much tighter seal but can still be deformed over time and should be worn for light swimming.  Screw-in case backs that are threaded and screwed into the actual case allow for the best seal.  This type of case back is typically found on true diving watches.  Gaskets, or “O” rings, are the final factor in creating a water resistant watch.  They create a water tight seal at the joints where any part of the watch meets the case, including chronograph pushers and crystal.

Damages To The Watch

Certain chemicals in the water can damage the watch seal.  Perfumes, some cosmetics, and strong chemicals such as gas, solvents or adhesives can cause some serious damage to seals and finishes on your watch.  While these are hopefully not found while you’re swimming, it is always good to be cautious when you’re out and about.

Salt water can also have a corroding effect on the seal and parts of the watch.  You should always rinse your watch with fresh water after exposing it to salt or chlorine.

Rating Scale

Meters and feet are very straight forward when you’re looking at the water resistance level. But what does BAR and ATM mean and how do they compare to meters and feet?  BAR is a unit of gauge pressure referring to the pressure above standard atmospheric pressure.  Sea level is defined as 1 BAR.  ATM refers to the standard atmosphere or standard pressure.

ATM at sea level is 1 ATM but converts to 1.013 BAR.  Scuba divers typically use ATM in relation to pressures that are relative to atmospheric pressure at sea level.  Typically BAR and ATM ratings will read the same amount even though they vary slightly.  Remember, the further you dive, the heavier the pressures become so make sure your watch has the right rating for the depth you’re diving.

Watch Dept Resistance


If you plan on swimming with your watch, have it water tested once a year.  This helps keep an eye on the gaskets and keeping a constant seal.  Never operate chronograph movements underwater unless your watch specifically states that it can be used.  Do not allow sudden and rapid air pressure changes.

Most deep water watches include a helium valve to ensure that air is release correctly without damaging the watch.   Although watches may be rated for depth, they have been tested in a controlled laboratory and may have different results in actual situations.  Double check your watch before immersing in water!

About Emily Smith
Newbie to watches but a quick learner. She loves the history of watches and loves learning how they work. She prefers Rolex and Omega watches but is learning the history behind other brands. Her watch of choice right now is her vintage Omega Ladymatic that is a mere 19mm. She has her eye on a few others including the Plum dial Rolex Oyster Perpetual 36mm and a Patek Twenty ~4 (4910/10 A011). While she enjoys the look of vintage watches, she is excited to learn about new models and build her collection.

Leave a Reply