These days we take it for granted that most luxury watches are water-resistant to some degree. However, at the turn of the 20th century, it was not yet standard for watches to be water-resistant. In fact, Rolex unveiled its Oyster watch in 1926 as the world’s first waterproof watch thanks to a patented architecture comprising of a screw-down caseback, screw-down crown, and a bezel clamping down the crystal. In 1931, Cartier introduced its own water-resistant watch in the form of the Tank Etanche and Omega followed suit with the Marine in 1932. In the late-1930s onwards, the waterproof watches Panerai supplied to Italian Navy frogmen had Oyster-style cases furnished by Rolex.
Fast-forward to the 1950s, and top watchmakers were trying to outdo each other by offering diving watches with improved waterproofness. The first modern dive watch was unveiled by Blancpain in 1953 rated to 91 meters deep. This was quickly followed by the 100-meter rated Rolex Submariner that same year, and then the 300-meter rated Omega Seamaster in 1957. Some watch brands have continuously focused on improving water resistance and today, there are some dive watches that can plunge as deep as 2,000, 3,000, and even 4,000 meters! That is well beyond the depths any human can survive.
But, have you ever stopped to wonder what does a watch’s water resistance really mean? How does it differ from a waterproof watch? And does a water-resistant watch stay that way forever?
Waterproof Watches vs. Water-Resistant Watches
While some watch brands, like Rolex, state that its watches are waterproof to a certain depth, the term “waterproof” can be misleading. No watch is 100% waterproof. In the United States, the Federal Trade Commission (FTC) disallows the term “waterproof” and recommends “water-resistant” instead.
The water resistance of watches refers to how much pressure a watch can withstand. Depending on where you are in the world, that rating is expressed in different measurements including feet, meters, atmospheres (ATM), and bars.
What Your Watch Water Resistance Numbers Mean
It is important to note that even if a watch states that it is water-resistant to 30 meters, it does not mean that the watch can dive down to 30 meters deep in the ocean. Those numbers were achieved in laboratory pressure tests with temperature-controlled and static water—and not out in the real world. External factors like water temperature, rapid changes in pressure, and accidental knocks, all affect a watch’s actual water resistance.
So what do the different water resistance ratings translate to in real life? Here’s a quick reference table (always refer to your watch’s official manufacture’s guide for accurate information):
Watch Water Resistance Guide
|No Water-resistant Rating||98 Feet, 30 Meters, 3 ATM, 3 Bar||165 Feet, 50 Meters, 5 ATM, 5 Bar||328 Feet, 100 Meters 10 ATM, 10 Bar||656 Feet, 200 Meters 20 ATM, 20 Bar||1,000 Feet, 300 Meters 30 ATM, 30 Bar|
*Does not apply to hot water
What Design Features Make a Watch Water-Resistant?
To become water-resistant, a watch has to be built in a way to prevent water from seeping into it. Therefore, any part that provides an opening into the watch—such as the crystal, the caseback, and the winding crown—must be designed to be airtight.
An important component of a water-resistant watch is the use of gaskets (often called O rings), which are rubber (sometimes in other materials too) pieces fitted onto the crystal, caseback, winding crown, and any other pushers, to create watertight seals. Unbeknownst to some watch owners, gaskets wear over time—especially if they are subjected to extreme temperatures or are constantly submerged in water. Worn out gaskets compromise a watch’s water resistance and they should be replaced regularly to maintain hermetic seals. Water-resistant watches do not remain that way without proper servicing and maintenance.
To achieve certain levels of water resistance, many luxury watches today have screw-down winding crowns and screw-down casebacks. It is imperative to always screw the winding crown back into place once you are done using it; otherwise, water will leak into the watch and damage it. Many high-quality water-resistant chronographs also have screw-down chronograph pushers. A watch can be fitted with a variety of different casebacks, ranging from snap-on metal casebacks to transparent crystal casebacks to screw-down casebacks. The latter is the most water-resistant of them all and is typical of top-tier dive watches.
Diving Watches & ISO 6425 Standard
There are many watch companies that market certain models as dive watches when they do not actually meet the criteria of an official diving watch. To be considered a diving watch, the timepiece must adhere to the ISO 6425 Standard, which among other things, stipulates that a watch much be water-resistant to at least 100 meters.
Watches rated for saturation diving are generally equipped with a helium escape valve. This mechanism serves to automatically release any helium build-up in the watch that can occur when the watch spends a lengthy amount of time in pressurized environments (such as SAT diving bells). Allowing the gasses to escape from the watch prevents internal and external pressure differences during ascension back to the surface, which can otherwise cause the crystal to pop off.
Get the Most Out of Your Water-Resistant Watch
- If applicable, always make sure all crowns and pushers are screwed in when you are wearing the watch
- Never operate pushers and crowns while the watch is submerged underwater
- Avoid subjecting your watch to extreme temperature changes, such as a hot tub session followed by a cold pool plunge
- If you spot moisture build-up under the crystal, send it in for repair right away
- Regularly service your watch for gasket replacements and water pressure tests
- If you purchase a pre-owned watch, do not trust its water resistance rating until you have had your watch pressure tested
- Vintage watches should never be considered water-resistant anymore due to their age