Water Resistant vs Waterproof Watches

Pop quiz: If your watch is marked water resistant for up to 100m, then you can swim down to 100m without damaging it, right? The answer? You can’t.

While we can all agree that water is the greatest enemy of a watch, understanding water resistance numbers is still a question to many watch owners, especially those who are just starting.

The terms “water resistant” and “waterproof” are often used interchangeably in the watch world, but they actually don’t mean the same thing. So what is a water resistant vs waterproof watch? Simply put, a water resistant watch can withstand contact with water for a certain amount of time, whereas anything waterproof should be technically be impervious to water.

Here, we’ll explain what your watch’s water resistance means, if a timepiece can indeed be waterproof, and what to do to protect your watch from water.

Understanding Water Resistance

In the watch industry, the water resistance rating means a watch’s ability to withstand water pressure. The depth rating indicated on your watch, such as 300m / 1000ft, is based on standard water resistance classification. These are tested on optimum conditions in a laboratory – such as a still-sitting diver or swimmer at a particular depth – which are very different from real-life situations.

Certain conditions such as diving into a pool, playing water sports, and coming into contact with salt water and hot steam can affect the amount of pressure a watch can handle and push water through its rubber gasket and into the movement.

This is one of the main reasons why watches should be serviced every few years – to ensure that the watch case remains robust and the seals are working as they should.
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pictured: Omega Seamaster 300M Diver Watch | SEE ALL STYLES >

How Water Resistant Is Your Watch?

Most mechanical watches use the measure ATM rating (or atmosphere rating) that specifies how many meters or feet the watch can be submerged in water without being damaged. An ATM is equal to 10 meters. It can also sometimes be referred to as BAR, most commonly used in Europe.

Before you come into contact with water, it’s always best to know your watch’s water resistant rating. Note that watches are tested for “static pressure”, and that movement – such as ones made by the arms while swimming – can dramatically change the actual pressure. This is why one should never use a watch near the official depth rating provided.

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rolex seadweller deepsea watch

pictured: Rolex Seadweller Deepsea | SEE ALL STYLES >

Watch Water Resistance Guide

Here’s a guide to how much water activity your watch can handle:

Water resistant : if your watch does not mention the ATM, don’t get it wet.

3 ATM (30 meters / 100 feet) : This is the most common level of water resistance, and is found in almost any luxury watch. This level has enough protection for only accidental splashes, and everyday use such as hand washing or rain. No showering or swimming.

5 ATM (50 meters / 165 feet) : These watches are perfectly fine for being submerged for short periods of time, such as brief periods of showering and swimming. No diving, vigorous swimming, or snorkeling.

10 ATM (100 meters / 330 feet) : This is the level of water resistance ideal for sports watches and daily wearers. It is safe to use for shallow water immersion, and water sports such as swimming, boating and snorkeling.

20 ATM (200 meters / 660 feet) : This level of water resistance is deemed safe for high impact water sports such as jet-skiing and recreational, shallow diving.

30 ATM (300 meters / 1000 feet) : You should be able to take this watch scuba diving, although they are not yet certified as ISO 6425 (diver’s watch).

The standards for calling a watch a “dive watch” are regulated by the ISO 6425, introduced in 1996. Diver’s watches are defined as those that can withstand diving in water at depths of at least 100m, and having a system to indicate the diving time, which should be visible in darkness.

Diving watches are tested in static pressure, or still water under 125% of the rated water pressure. Watches are considered water resistant if they are stationary under 250 meters of static water.

100 ATM (1000 meters) : These watches belong to the realm of saturation diving, specifically designed for use in challenging underwater conditions. These watches are thick, with extremely robust sapphire crystals, and are suitable for mixed gas diving.

rolex seadweller and rolex seadweller deepsea watch

Can Watches be Waterproof?

The term waterproof connotes that something is not penetrable by moisture and will not leak, but under certain conditions anything can leak. In fact, while the term “waterproof” is often thrown around in talks of watches, it has been discontinued by the Federal Trade Commission from watch labels since the 1960’s.

The term “waterproof” has been gradually replaced by “water resistant” in watch labels. Today, there are two standards by which watches are tested for their water resistance. The ISO 2281, for water resistant watches, and the more rigorous ISO 6425, for diver’s watches.

So the truth is, there is no such thing as a waterproof watch ; there are just varying degrees of water resistance.

In the case of Rolex, every one of their Oyster case watches are water resistant to 100m. Their dive watches – the Rolex Submariner, the Seadweller, and the Deepsea – improve upon this with water resistance rating of 300m, 1,220m, and 3,900m respectively.

The Rolex Sea-Dweller Deepsea, as said, is water resistant down to a 3,900 meter water depth, or nearly 13,000 feet – but still does not brand itself as waterproof.

No watch can be truly considered waterproof, but a Rolex dive watch is as close as one could come.
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pictured: Rolex Seadweller and Rolex Deepsea | SEE ALL STYLES >

Should you want to get wet with your watch, follow the guide above. Always ensure that the crown is properly screwed down, to prevent water from entering your watch. And if you’re not sure, always err on the side of dryness. Better safe than sorry!

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