This is probably the most misunderstood figure in watchmaking. A watch marked 3 ATM, or 30 meters, cannot go 30 meters underwater. This confusion costs thousands of watches every year. Let's be clear.
What an ATM truly measures
One atmosphere (ATM) corresponds to the pressure exerted by 10 meters of water. But the test is done in the laboratory, on a stationary watch, in still water. No one swims stationary.
A arm movement multiplies the instantaneous pressure far beyond the actual depth. A dive from the edge of a pool creates a peak higher than that of several tens of static meters. A meter indication is therefore not an authorized depth: it is a measure of resistance under laboratory conditions.
The table we would have liked to see before buying
- 3 ATM — Splashes, rain, hand washing. No showering, no swimming pool, no sea.
- 5 ATM — Same, plus an occasional shower. Swimming is still not recommended.
- 10 ATM — Surface swimming possible. No diving, no water sports.
- 20 ATM and more — Diving. This is the threshold for true diving watches.
Our watches are 3 ATM, and we state it
Our 316L stainless steel cases are water-resistant to 3 ATM. Concretely: you can wash your hands, be caught in the rain, spill a glass of water. You cannot swim, shower, or go into the sea.
We prefer to write it rather than let a flattering number do the work. A slim, quartz watch, under sapphire glass, is not designed for water: it is designed to be worn every day — like the Tourmaline or the Muguet.
Three mistakes that let water in
Handling the crown when the watch is wet
This is the most frequent cause. The crown is the most vulnerable point of the case: pulling it with wet fingers is opening the door. Always dry the watch before setting the time.
Thermal shock
Going from a sauna or an overheated car to cold water makes the gaskets work and can create condensation under the glass. Fogging inside the dial is a warning sign: have the watch checked.
Forgetting that gaskets age
Water resistance is not lifelong. Rubber gaskets harden with age, heat, and cosmetic products. On a 3 ATM watch worn normally, this is not a concern; it is one more reason not to wet it voluntarily.
The useful reflex
If the watch takes on water despite everything, do not shake it or place it on a radiator. Remove it, dry the exterior, and have it opened quickly by a watchmaker: water attacks the movement in a few days.
Note: water damage is not covered by our 24-month warranty, which covers manufacturing defects.
Choosing knowingly
If you are looking for a watch to wear at the office, in the evening, and everyday without thinking about it, 3 ATM is more than enough: our women's models and our men's models are made for this use. If your day involves the pool or the sea, opt for a watch specifically designed for that — we prefer to tell you than to see you come back disappointed.
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