The Difference Between Waterproof And Water Resistant Watches

A question that a lot of people ask is; are water-resistant and waterproof watches the same? The quick and straightforward answer to that question is no.

Although the two phrases might sound similar, they are not the same. So be careful when you take your water-resistant watch diving.

In this post, I will guide you through the differences between waterproof and water-resistant watches.

Read on to find out more.

The Squale Atmos Is Rated 20 ATM (200m)

The Definitions Explained

Waterproof: A waterproof watch is entirely impenetrable to water penetration, which means no water can get in or out.

A waterproof watch will give the wearer protection from water for a significant period of time.

Water-Resistant: A water-resistant watch will prevent water penetration to a certain level.

Because this is not totally impenetrable, the watch will let water in or out when exposed to high levels.

Think about a lot of pressure when you’re deep underwater.

So, the fact that a watch is water-resistant does not mean it is waterproof.

This misunderstanding can create problems.

But it is an understandable mix-up; the word resistant says it will keep water out, right?

Because of this mix-up, many people go swimming or even diving with their water-resistant watch, only to find out that it has let water inside.

After all, no one wants to damage their timepiece with water, and the repair costs for water damage are high.

Water-Resistance Tests

There are several tests to test whether a watch is water-resistant or waterproof.

You could use a dry test like a vacuum test, but it cannot specify the level of pressure that is applied.

So you would never know the specific degree of water resistance.

A wet test, like a pressure test, works with water.

Air flows from high-pressure areas to low-pressure ones.

When the chamber is pressurized, if there are any leaks in the watch, air will get into the case; when the chamber gets depressurized, the air will come out of the case.

Add water to that chamber, and you will see bubbles come out of the watch case when the chamber gets depressurized.

If a watch manages to go through the whole test without failure, it passes the water-resistance test.

If the watch fails a test and it should be water-resistant or waterproof, take it to a watchmaker who can close up the leaks for you.

The Speedmaster Reduced Has No Rating On The Dial But Is Rated For 3 ATM (30m)

Water-Resistance Ratings

After a passed test, it is good to know what kind of water-resistance rating your watch got.

In this table, you will find the most common water-resistance ratings on watches.

It starts at 3 ATM, where the watch is resistant to splashing but not for swimming or a shower.

From 5 ATM, you can take it under the shower or into the pool.

Watches above a 5 ATM rating are waterproof up to a certain level, and you can wear them during snorkelling or even up to deep-sea diving if you have a watch that has a rating of 100 ATM.

RatingDepth (m)Depth (ft)Suitable for:
3 ATM30 Meters100 FeetRain, Splashing
5 ATM50 Meters164 FeetRain, Splashing, Showering, Surface Swimming
10 ATM100 Meters328 FeetRain, Splashing, Showering, Surface Swimming, Snorkeling
15 ATM150 Meters492 FeetRain, Splashing, Showering, Surface Swimming, Snorkeling, Surface Diving, Water Sports
30 ATM300 Meters984 FeetRain, Splashing, Showering, Surface Swimming, Snorkeling, Surface Diving, Water Sports, Scuba Diving
100 ATM1000 Meters3280 FeetRain, Splashing, Showering, Surface Swimming, Snorkeling, Surface Diving, Water Sports, Scuba Diving, Deep-Sea Diving

The Certina DS Action Is Rated At 30 ATM (300m)

Keep A Watch Water-Resistant

You can keep your watch resistant to water by testing it once a year at a watchmaker.

If there are any leaks, he can fix them; if you use the watch more often in the water, watchmakers recommend replacing a watch its gasket once per year to prevent loss of water resistance.

Also, don’t go to a sauna with your watch since steam is different from water and could sneak through the gasket into the watch.

After beach days or days at sea, do not forget to wash off salt water from the watch with tap water to avoid corrosion.

And last but not least, do not take your watch to an activity higher ranked than what its rating is.

So take care of your watch; it will last you a lifetime.


The guy who loves to chat about watches.

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