ARVENIER
Watch water resistance ratings describe the pressure a watch survived in a lab test, not a depth you can dive to. In practice, 30 m (3 ATM) means splash-resistant only, 50 m (5 ATM) handles brief swimming in a pool, 100 m (10 ATM) suits regular swimming and snorkelling, and 200 m or a true diver's rating is needed for scuba. Heat, soap and ageing seals reduce resistance over time.
What do the water resistance ratings mean?
The numbers are pressure ratings expressed as metres, atmospheres (ATM) or bar, which are roughly equivalent. They come from tests in still water under ideal conditions; real movement, temperature changes and old seals all add stress.
- Water resistant / 30 m / 3 ATM: rain, splashes and hand washing. Not for showering or swimming.
- 50 m / 5 ATM: showering with cool water and short, gentle swims. No diving in.
- 100 m / 10 ATM: swimming, snorkelling and water sports at the surface.
- 200 m / 20 ATM: serious water sports and recreational diving.
- Diver's watch (marked DIVER'S with a depth): built and tested for scuba under a specific international standard.
Why is a 30 m watch not safe for swimming?
A swimming stroke, a dive into a pool or a jet of water creates brief pressure spikes well above still-water pressure. A watch rated at 30 m is designed to survive accidental splashes, not repeated immersion. Water resistance is also standardised internationally (ISO 22810 covers everyday water-resistant watches), and the test assumes a new watch with intact seals.
What reduces water resistance?
- Hot water: hot showers, baths, saunas and steam rooms make gaskets expand and contract.
- Soap, shampoo and sunscreen: they degrade rubber seals over time.
- Pressing buttons or pulling the crown underwater: this opens a path for water.
- Age: gaskets dry out after a few years, especially after a battery change if seals are not replaced.
- Knocks: a cracked crystal or dented case breaks the seal.
How to look after a water-resistant watch
Rinse a watch in fresh water after the sea or a chlorinated pool, then dry it with a soft cloth. Make sure a screw-down crown is fully closed before contact with water. When the battery is replaced, ask for the seals to be checked or replaced too, and avoid opening the case yourself. Leather straps should stay dry whatever the case rating, because water stiffens and cracks leather.
What to do if water gets inside
If you see fog or droplets under the crystal, stop using the watch in water, remove it from the wrist, and take it to a watch repairer quickly. Moisture inside a quartz watch can corrode the movement within days. Do not leave it in the sun or on a heater to dry; heat can make things worse.
Frequently asked questions
Can I shower with a 5 ATM watch?
A cool, brief shower is usually fine, but hot water and soap wear the seals faster. Taking the watch off is the safer habit.
Is waterproof the same as water resistant?
No. No watch is fully waterproof; manufacturers use 'water resistant' with a rating because resistance has limits.
Does a smartwatch follow the same ratings?
Many use ATM ratings or IP ratings such as IP68. Check the manufacturer's guidance on swimming and showering for that specific model.