Watch water-resistance: watch out for the trap!
When choosing a watch, there are many aspects to consider. Water-resistance is one of them. Let's take a look at how not to make a mistake, depending on how you plan to use your watch in the future...
Note: Some watches, because of their complications and the way they are made, cannot logically claim to be very water-resistant. For example, an automatic watch with an open mechanism (open heart, skeleton...) will rarely be more than 30 ATM (300m), just as a very water-resistant watch will rarely be particularly thin.
History of water resistance in watches
The evolution of water-resistance in watches has had a significant impact on the history of watchmaking, moving from simple protection against humidity to devices capable of withstanding extreme depths.
In their early days, watches offered little resistance to water, often making do with slightly reinforced cases to repel dust and surface moisture. That all changed in 1926 with the Rolex Oysterthe first watch with a completely sealed case. This innovation made it possible to protect the inside of the watch - dial and hands - from any water intrusion, marking a decisive turning point in the design of water-resistant watches. This model paved the way for advances that have enabled diving watches to meet and exceed increasingly stringent underwater resistance standards. Until then, a water-resistant watch was simply waterproof, but thanks to Rolex, models have become waterproof, allowing you to enjoy a dive or a swim in the ocean to the full.
Emblematic models
The Rolex Oyster is often cited as the pioneer of waterproof watches, but it is not alone. The Omega SeamasterIntroduced in 1948, the Seamaster pushed the limits of water resistance to meet the needs of professional divers and water sports enthusiasts. Initially designed for everyday use while offering superior water resistance, the Seamaster has evolved to include features specific to underwater environments, such as rotating bezels for measuring dive time and dials that are highly legible underwater.
These innovations are not just technical advances, they have also transformed the watch from a simple tool into a reliable companion for underwater explorations, demonstrating the watch industry's ability to combine form, function and reliability.
Standards guide and correspondence
Here's a table to help you quickly understand the fine distinction between waterproofing and actual use. Metrics to keep in mind when making your purchase!
| Resistance index | Resistance | Recommended activities |
| Splash-proof | 3 ATM (30 metres) | Withstands splashes, rain and hand washing |
| Water-resistant | 5 ATM (50 metres) | Shower, surface swimming |
| Waterproof | 10 ATM (100 metres) | Swimming, diving in the pool |
| Very watertight | 20 ATM (200 metres) | Sport diving |
| Dive-proof | 30 ATM (300 metres) and more | Professional diving with equipment |
As you can see, a 3 ATM (30 m) watch does not allow you to dive underwater, even at one metre. Similarly, if you want your watch to last over time, it's essential to choose a stainless steel bracelet rather than a leather strap, which will wear out much more quickly.
Note: Serious manufacturers use special machines to test their products for water-resistance. In the event of non-compliance, the watches are returned to production.
Understanding waterproofing certification
The most widely recognised standard for water resistance in watches is ISO 22810. Adopted internationally, it defines the requirements for watches intended for use in water, stipulating not only the minimum depth of resistance but also how this resistance is to be tested. Contrary to what many people think, a watch certified for a certain depth (e.g. 50 metres) is not necessarily designed for diving at that depth, but rather must withstand the equivalent pressure in a controlled environment. This includes tests for resistance not only to static immersion but also to temperature variation, the force of water jets, and water ingress when using the watch's functions underwater.
Care after exposure to water
Even watches designed to be water-resistant require appropriate care after immersion to ensure their longevity and functionality. Here are some practical tips for looking after your watch after it has been exposed to fresh or salt water.
After each immersion in salt water, it is essential to rinse your watch thoroughly in fresh water to prevent salt and other minerals from causing corrosion or damaging the seals. Use lukewarm water and, if necessary, a soft bristle brush to remove salt particles and small debris. Make sure you also dry the watch completely with a soft cloth to avoid residual moisture, which can be just as harmful as salt. This step is crucial, especially for watches not specifically designed for sea diving but which have been exposed to salty conditions.
Damaged watch? Our advice
The importance of maintenance for the reliability of water-resistant watches
When a watch is described as waterproof, it should theoretically be water-resistant. However, the reality is often more complex, and several essential parameters need to be considered to maintain this functionality.
Joint maintenance is crucial
The good condition of the gaskets is vital for protecting the inside of the watch. Seals must be regularly checked for wear and properly lubricated with suitable products. Without this, they become vulnerable and may no longer prevent water from penetrating, especially if the seals are affected by fluctuating temperatures or adverse weather conditions.
Water quality counts
It is also essential to take into account the type of water in which the watch is immersed. Even if the water appears clear, it may contain corrosive elements, such as the salt in seawater, which can degrade the rubber gaskets and compromise water-resistance. The indications provided by manufacturers are often based on tests carried out in optimal conditions, such as fresh water with a neutral pH, which is not representative of all exposure situations!
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