How Much Water Resistance Do We Actually Need?

How Much Water Resistance Do We Actually Need?

Dive watches being more popular than ever with both watch enthusiasts and novices alike, one may wonder how much water resistance do we actually need on a daily basis? What does having a water resistant watch mean in the first place, anyway? In this article, I wanted to take a quick look at what it means to have a water resistant timepiece and how much of it do we need—actually—in our daily lives? There are many discussions (some of them unnecessarily heated) going around the watch community about this topic. And of course, my goal is to only share my humble opinion. So let’s dive in! (Perfect pun, isn’t it?) 

Rolex Deep Sea Source: 

Water Resistant vs. Waterproof 

First things first, let’s address the fact that there is no such thing as a waterproof watch, in the sense that there is no watch that is 100% protected against water. Water can and will eventually find its way inside the case by way of a poorly screwed case back, a dried up gasket, or poor tolerances on the bezel construction. Yes, dive watches back in the days used to display the word “waterproof” on their dial, but it no longer is the case. It has become known and accepted that a watch cannot be waterproof but only water resistant. And it doesn’t matter whether it can be water resistant to 50 meters or 1,000. It’s only water resistant. 

The fact that we can now logically talk about water resistance instead of waterproofness reflects the more stringent tests brands have to go through in order to to indicate how deep their watches can go. If a watch shows 100 meters of water resistance, it theoretically means you can dive with your watch up to 100 meters of depth and that no water will enter the case. If you go 150 meters, then water can get inside and you are out of luck. Your watch was engineered to sustain 100 meters of depth. But this is not always the case and it depends whether or not the watch was certified as being able to go 100 meters deep.  

Water Resistant Watches Source: 

ISO Certifications & Testings 

There are two standards for water resistance in the watch world: ISO 22810 and ISO 6425. Besides these two, some brands have their own in-house testing regiments but they don’t follow the ISO requirements. Brands like Rolex and Omega run their own tests and are said to exceed the requirements of either ISO certifications. Which means their watches are definitely water resistant to the depth indicated on their dials. The ISO certifications exist to create an international standard to guarantee that a watch can be submerged in water. But these two certifications were not created equal, as we will see below. 

Of the two, ISO 22810 is the easiest to pass. It only tests for water resistance (more on that later) and the watch is tested to 100% of its depth rating, meaning that if a watch indicates 100 meters of water resistance, it will be tested to 100 meters. And the test is made inside a pressurized device and runs for 10 minutes. What the test is supposed to show is that the watch can withstand 10 bars of pressure. This is the kind of test that most of your local watchmakers will run as it is easier and cheaper to test water resistance this way. This method, by the way, is known as “dry” testing. 

ISO 6425, on the other hand, is much stricter. Water resistance is tested to 125% of the depth rating (meaning that a watch with a water resistance of 100 meters will be tested for 125) for two hours. The watch will also be tested for shock resistance, resistance to corrosion and magnetic fields. The most important part, perhaps, is the fact that ISO 6425 is a “wet” type of testing meaning the watch is put inside a water tank. (By the way, there are more that goes into 6425 to make a watch a diver; we’re only talking about water resistance here.) 

Now that we discussed what water resistance is and what kind of testing can be done to guarantee it, let’s discuss what we actually need on a daily basis. 

Water Resistance Test DYI Watch Club Source:

What Do We Need? 

Naturally, if you are a professional diver you need a proper dive watch. Commercial divers that go several hundred meters deep definitely need a watch built for such depths. But how many of us need 200 meters of water resistance? Many watch enthusiasts and journalists (including myself, for a very long time) rave about proper dive watches that come with 200 or 300 meters of water resistance, as being the gold standard. However, looking at the watch community from a global perspective, I bet you don’t need this much water resistance 99% of the time. (Unless, as stated above, your profession requires it.) 

The common wisdom is that an everyday watch should have at least 50 meters of water resistance. This guarantees that you can wash your hands and get rained and that no water will enter the case and therefore damage the movement. (If that were the case, however, the trick is to put your watch in a bag of rice in a dark place for three days which will remove all water and humidity from inside the case.) Some would argue that it would be safer having 100 meters of water resistance and that anything below that is worthless. (That’s when the heated debates begin!) 

If you are a watch nerd, you have most likely spent a lot of time thinking about screw-down crowns and whether or not they are necessary to guarantee water resistance. They aren’t. Their purpose is to keep dirt and dust particles away from the movement, and that was perhaps a bigger worry 100 years ago (when the first screw-down crown and case-back watches were created by Rolex) than it is now. A push-pull crown is now more than enough to guarantee 100 of water resistance. Personally, I still prefer to have a screw-down crown for the added piece of mind—but it is absolutely not necessary. 

Rolex Datejust Chrono24Source:

Final Thoughts 

While having 200 meters of water resistance, a screw-down crown and case-back on your watch is a bonus and guarantees high levels of water resistance and protection, we don’t actually need any of this on a daily basis. This is not to say that you shouldn’t want it, of course not, however you should feel reassured that 100 meters of water resistance and a push-pull crown is more than enough for everyday wear. At the end of the day, wear what makes you happy. By writing this article, I merely wanted to shed some light on the myths of water resistance and waterproofness and what is enough for most of us on most occasions. 

Don't forget to get the right strap for your diver, especially if you have a Submariner.

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