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.
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.