Easily one of the most misunderstood terms when it comes to watches is “water resistant.” Generally, if a watch is water resistant, it says it is – and to what depth – on the case. However, that doesn’t mean you can jump in the shower or a deep pool with your watch on. There are guidelines to understanding just how water resistant your watch is.
To begin with, it is important to know that watches are not “waterproof” – only water resistant. The idea of waterproof leads one to believe that water won’t get in no matter what, but it isn’t that easy. This is because all watches have a limit to how much pressure (and shock) they can withstand before moisture will get into the case and movement. As such, the term water resistant is more accurate because it is all about the pressure that the watch can handle. That pressure is usually measured in either atmospheres (ATM), bars, meters, or feet.
Depth Guide for Water Resistance
All watches that are water resistant use one of several terms to indicate how deep the wearer can take the watch. It is important to understand those terms and their translations.
Essentially, if a watch is water resistant to 1 atmosphere (ATM) it is water resistant to 1 bar, or 10 meters, or approximately 33 feet. With this in mind, you can use the following scale to determine the depth a watch can go to.
1ATM = 1 Bar = 10 meters = 33 feet (approximately)
10 ATM = 10 Bar = 100 meters = 330 (approximately)
20 ATM = 20 Bar = 200 meters = 660 feet (approximately)
30 ATM = 30 Bar = 300 meters = 1000 feet (approximately)
50 ATM= 50 Bar = 500 meters = 1,640 feet (approximately)
and so on and so forth
Finding Out How Water Resistant Your Watch Is
You can see the water resistance rating of your watch by taking a look at the dial or case back. If your watch does not say water resistant, it is not. Take it off before washing your hands, and don’t wear it out in a rainstorm.
If it is stamped water resistant without any depths indicated, that typically means it is just humidity protected. Maybe it can get caught in the rain with you, but don’t swim with it on.
If your watch is water resistant to a particular depth, that will be stamped on the watch somewhere highly visible – usually the case back.
30 meters means it can resist some splashing
50 meters means it can go in a pool for a short time or for a swim in the ocean
100 meters means you can take the watch on a snorkel trip with you and wear for a prolonged time in the water
200 + meters means you can dive with the watch, but there are typically other factors built into a good dive watch.
Dive Watches
Depending on how deep you dive, you need a watch that is designated for the sport. Dive watches should be water-resistant to at least the Diver’s International Organization for Standardization ISO 6425 standard. This states that a watch should have a minimum depth rating of 100 meters, which is ok for snorkeling and swimming, but for serious dives, it is best to have a watch that is water-resistant to at least 200 or 300 meters. (Keep in mind that some brands offer higher water resistance, such as 500 meters and even 1,000 meters. Rolex offers one particular SeaDweller watch that is water resistant to 1220 meters.)
Often dive watches are COSC-certified chronometers (watches that have undergone rigorous testing in various positions and under different conditions of pressure, temperature, depth, and gravity, usually by the Controle Official Suisse des Chronometres (COSC) observatory over a period of time).
Most dive watches are also equipped with additional functions or features that include such things as a double- or triple-locked winding crown (often oversized), additional gaskets, and silicone O rings. Screw-down case back, screw-in crown, and crown protectors. These all help to keep the watch resistant to water.
Some more important dive watch features are the graduated one-way rotating bezel that clicks into place and measures elapsed time underwater and helium escape valves for deep dives and resurfacing. These valves allow the gas built up inside the watch during the descent and underwater time to escape slowly as the diver ascends.
Some dive watches indicate bottom time and/or have an alarm function that can be sensed underwater. Many come with interchangeable bracelets or straps or with an extension clasp so the watch can be worn over the wet suit. Almost all top-notch dive watches have double-lock clasps for added protection against loss in the ocean.
Can You Dive Off a Diving Board With Your Watch On?
Unless your watch is also shock resistant to high standards, it is a good idea to take it off before diving off of a diving board or ship’s deck. The shock of hitting the water and of the immediate pressure change can damage the timepiece.
Can You Shower With Your Watch On?
It is not recommended to shower with your watch on, even if it is highly water-resistant. This is because the abrasive chemicals in the soap or shampoo you use can slowly erode the rubber gaskets and compromise the watch’s ability to keep water out.
Finally, it is a good idea to periodically have the gaskets in your water-resistant watch checked by an authorized service center.
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