The water resistance of a watch is the property of the case to prevent moisture from passing into the watch mechanism. The degree of water resistance is usually specified in meters or atmospheres. Immersion to a depth of ten meters corresponds to an increase in pressure of one atmosphere. This function was first implemented by Rolex in 1926. The designation "water resistant" is used for watches that must not come into contact with water. The maximum water effect for them is air humidity. If you have a watch with this designation, please pay special attention to it. You should not take this watch with you into the bathtub or swimming pool if you do not want to lose it in a few seconds. Watch manufacturers are not allowed to label watches as waterproof , even if they are watch models designed for deep diving. Although we may encounter this designation from some dubious manufacturers and their distributors, definitely do not believe it.
We have these different levels of water resistance for watches
Water resistant 3 ATM/ Water resistant 30 meters Withstands contact with water when washing hands, showering or in the rain, for example. However, this watch should not be submerged. Water resistant 5 ATM/ Water resistant 50 meters Suitable for surface swimming, jumping into the water is not recommended. Water resistant 10 ATM/ Water resistant 100 meters Snorkeling, diving without breathing apparatus (approx. 10 meters below the surface) and general frolicking in the water with more vigorous movements (sport). Water resistant 20 ATM/ Water resistant 200 meters Designed for recreational diving with breathing apparatus up to approx. 40 meters. Water resistant 30 ATM/ Water resistant 300 meters Professional diving with breathing apparatus. From this limit, the watch is usually equipped with a helium helium valve . Water resistant 100 ATM/ Water resistant 1000 meters Made for deep diving, they are impregnated with "oil", or have sealing rings that can withstand the helium used in decompression chambers. They probably have pressure relief valves that release the helium that leaks into the watch during surface treatments, thus preventing the watch from exploding. Other water resistance values Higher values are usually used for professional watches for deep diving. There may also be various anniversary models with non-rounded ATM values, which is caused, for example, by the fact that the premium model is marked with water resistance in feet - i.e., for example, 2,000 feet = 61 ATM. The "water resistant" designation together with the depth designation in meters or pressure in atmospheres (atm) is used for more resistant watches. The water resistance of watches is commonly stated in three different units: meters (m), bars (bar) or atmospheres (atm). All three units refer to one quantity, which is the pressure of the water column that acts on the watch. 1 meter of water column corresponds to a pressure of 0.1 bar or 0.1 atmosphere. So when a watch says 100 m, 10 bar or 10 atm, it always means that the watch can withstand the water pressure in laboratory conditions, which is 100 meters at the temperature and density of water specified by the standard. However, there is often a mistaken assumption that this value also means the depth to which the owner of the watch can dive with the watch without harm. Theoretically, this is the case, but assuming that a person dives into clean, calm water without movement and at a constant temperature. However, such a situation is more than unlikely, the actual safe depth in everyday life is much lower. Watch tests are carried out in laboratory conditions and therefore under ideal conditions. But these do not normally occur when diving. The stress on a watch underwater also depends on how you move with it, whether you hit something with it. If you dive in the sea, it is threatened by aggressive salt water and chemicals. It is generally said that a watch marked as resistant to 30 meters / 3 atm is suitable for washing the car at most, but you should not take it for swimming. You should only swim with a watch rated for 100 meters / 10 atmospheres. For diving with equipment, only watches that can withstand a depth of 200 meters, i.e. 20 atm, are suitable, and professional diving watches are marked as 1000 meters / 100 atm.
