What is Water Resistance Rating?
Water resistance rating is the maximum depth of water pressure that a watch can safely be submerged into without damage.
Water resistance is tested by the manufacturer at the time the watch is made. It may also be written on the dial.
Is Water Resistance Permanent?
The water resistance rating is written under the assumption that the watch is in perfect working condition.
Take a dive watch such as the Orient Kamasu (Amazon), for example. When brand new, it has a 200m water resistance – perfectly safe for swimming, diving, showering, etc. However…
Over time, seals, gaskets, and other parts of a watch that keep a watch’s original water resistance rating tend to wear down. Once these parts wear down, the water resistance rating starts to degrade as well.
Just like the specifications of a car. You might expect it to work perfectly the day you leave the dealership. But over time, and with use, parts wear down and don’t work as well as they once did.
A watch that was originally purchased with a 200m water resistance might not be as water-resistant as it once was, when you originally purchased the watch.
This is especially important to keep in mind when it comes to older vintage watches, or watches bought secondhand.
If you’re buying vintage or used watches, it’s important to ask the seller if and when the watch was last serviced, and had if it had its water-resistance tested by a watchmaker.
Now that you know what water resistance is, how much water resistance do you really need?
What Water Resistance Do I Need For Swimming, Diving, or Showering?
For diving, you want a watch with at least 200m water resistance. This means the watch can be submerged up to a maximum depth of 200m without damaging the watch.
If you are a diver and take the hobby seriously, it is highly suggested you use an ISO-certified dive watch, such as the Seiko SKX.
ISO certified dive watches must maintain a certain set of specifications to be approved for the ISO certification. These are a must for professional divers, in case your scuba air monitor fails.
You want to have a reliable and working dive watch to time your dives, and to make sure you safely have enough time to reach the surface without running out of oxygen in your tank.
When swimming, since you’re not submerging the watch into as heavy water pressure as if you were diving, you can wear a watch with slightly less water resistance rating.
When swimming, you want a watch with at least 100m water resistance.
Again, this is assuming your watch is regularly maintained and serviced.
Going for long periods of time (5+ years) without a service means your watch has likely lost some of its waterproof rating since.
In general, I suggest picking up a cheap beater watch for swimming. Even a cheap dive watch like the Casio MDV Duro, or a G-Shock will be more than suitable for swimming. They’re both affordable and readily available on Amazon.
Plus, if they were to get damaged, you’re not out that much money, since they’re so affordable. Much better than risking your beloved vintage Rolex Submariner that hasn’t been serviced in a long time.
There’s the old saying, “just because you can do something, doesn’t mean you should”.
That’s the case with showering with your watch on.
Generally, you can shower with watches that have at least 100m water resistance.
But just because you can shower with a watch on, and it doesn’t seem like it got water damage, doesn’t mean your watch didn’t actually get damaged.
Typically, the heat and steam from showers will slip into the watch even easier than water would.
This heat and steam will then degrade the integrity of the watch’s seals and gaskets and make your watch less water resistant in the future.
Steam could also get inside of the watch and moisture could potentially rust the inner workings of the watch movement.
Overall, it is suggested to avoid showering with your watch on.
Which Watches Have the Best Water Resistance?
While water resistance isn’t a feature specific to any one type of watch, dive watches are typically made for divers and thus, will often have the highest water resistance ratings.
Of course, even within the category of dive watches, there are various degrees of water resistance ratings.
For example, the new Seiko 5 Sports Divers only have a 100m water resistance.
One thing to note is that more expensive watches don’t always have better water resistance ratings.
For example, the Casio MDV Duro, an extremely affordable dive watch, boasts an impressive 200m water resistance rating.
Why Water Resistance Isn’t the Only Factor
Water resistance rating isn’t the only factor in determining whether or not your watches can get wet.
A water resistance rating is just the initial rating given by the manufacturer at the time the watch leaves the factory.
Over time, this water resistance might degrade.
Additionally, watches with screw-down crowns, chronograph pushers, or any other functional external factor, need to be used carefully.
If your watch has a screw-down crown, it needs to be screwed down in order to seal the watch, and maintain the listed water resistance, thus keeping it waterproof.
An Apple Watch is an exception, as it is a digital watch. Still, if you are wearing your Apple Watch in water, make sure you turn the ‘water lock’ feature on, and do not disable it while it is submerged.
Chronograph watches or any other watches with a physical button need to not be pressed when submerged in water, even if they have a high water resistance rating.
Regardless of the water-resistance rating, pushing a button on a watch while it is submerged in water will almost certainly allow water to enter your watch. A recipe for disaster.
How to Test A Watch’s Water Resistance
Let’s say you buy a watch with any particular water resistance rating (30m, 50m, 100m, or 200m). You’ll often want to test that the water resistance is accurate before getting your watch wet. How can you test a watch’s water resistance?
Unfortunately, there is only one safe, tried, and true method in testing your watch’s water resistance.
This is… Not by taking a swim, and hoping for the best.
The most reliable way to test your watch’s water resistance is by taking it to a reputable watchmaker where they can perform specialized pressure tests.
While I would love to recommend you a DIY Water resistance test, getting an accurate reading is only truly done through highly specialized and expensive water pressure testing equipment.
Most watchmakers have access to this type of equipment and will charge a small fee to run this test for your watch.
If you get lucky, or send your watch in for a full maintenance service, some watchmakers may provide this service as a “final-step” after servicing you watch.
It could be worth it, though, and save you potential water damage and headaches down the line.
The Final Verdict
Water resistance is an extremely important measure of how waterproof your watch is.
200m is generally appropriate for diving. 100m for swimming and showering. 50m and 30m for washing your hands, or getting caught in the rain.
But just because your watch has a water resistance rating written on the dial doesn’t mean it’s waterproof. You’ll still need to regularly have your watch serviced, maintained, and tested to be 100% certain the water resistance rating is still accurate.
Last update on 2021-02-17 / Affiliate links / Images from Amazon Product Advertising API