Based on many years of experience in selling and servicing watches, we noticed some frequent doubts regarding the meaning of waterproof labels. In order to safely wear a watch when in contact with water, hereby please find detailed explanation of the meaning of water-resistance, work environment, FAQ, and an overview of useful information.


  • WR - watch is not water resistant - Avoid any contact with water.
  • WR 30m/3ATM/3bar - Will withstand splashes of water but should not be worn while swimming.
  • WR 50m/5ATM/5bar - Will withstand splashes of water (washing hands, rain, humidity) but should not be worn while swimming.
  • WR 100m/10ATM/10bar - Suitable for swimming and snorkelling.
  • WR 200m/20ATM/20bar - Suitable for skin diving (apnoea diving).
  • WR 300m/30ATM/30bar and more - Suitable for scuba diving and professional diving.
Water is the most common cause of watch malfunction! Do not be misled by marked water-resistance ratings expressed in meters on the watch! This rating refers to depth/pressure in which both water and watch are absolutely motionless, and such conditions are achieved only in optimum conditions in laboratory tests. In practice, the force of plunging your arm into the water while swimming dramatically increase pressure on the watch, therefore it will not withstand a dive to the depth specified on it.

What makes a watch water resistant?

There are several characteristics that make a watch water resistant. The most important are gaskets (O-rings) made of rubber or teflon which use as seals where crystal, case-back or crown meet the case of the watch. If the watch has a chronometer, chronometer push buttons also have gaskets.
The density and type of materials used for watch case are also an important factor in the quality of water-resistance. Watch case must be strong enough to withstand the pressure without deforming the material. Screw-down case back, contrary to snap-on case back, also contributes to water-resistance.
Screw-down crown, which is mostly found in sport-diving watches, helps preventing water penetration through the crown stem hole.

Why a watch rated "WR 50 / water resistant 50 meters /" in the instruction manual states that watch is not suitable for diving, but only slightly spraying?

Different levels of resistance to water, which are usually expressed in meters, are only theoretical. They refer to the depth at which the water and watch are absolutely motionless. Such conditions are never met in "real life" and can be achieved only in laboratory tests, not in the sea. The movements of the hands through water dramatically increase the water pressure. So, it is not safe to wear a watch at depth indicated on the watch.

What does the abbreviation ATM used in marking the level of water-resistance mean?

It represents  "atmosphere" and is equal to 10 meters depth/water pressure.
Another word for  atmosphere is "bar".

Is water-resistance forever?

No. Water-resistance of the watch depends on several factors. Some of these factors are influenced by the weather changes and manners of wearing a watch. Gaskets could corrode and distort, case may be damaged, and crystal scratched or cracked. Therefore the watch needs regular maintenance and service.

When does the watch lose its water-resistance?

. When diving into the water (as the impact produces a pressure that by far exceeds that to which the watch is resistant and it is a shock that should be avoided at all cost), . When operating crown or any push buttons while under water, with wet hands, or while the watch is wet, or while the watch is in any contact with water, . When showering or in sauna / hot water, steam, and large temperature differences cause deformation of gaskets, water condensation in the watch and loss of water-resistance, . If the crown is not fully pushed into the case, or if a watch has screw-down crown and push buttons -  if they are not fully tightened into the case, . If the crystal, crown or any  push buttons are damaged, or if the watches was already banged, . If the watch was opened and was improperly closed.

How often is it necessary to check water-resistance?

At least once a year. Most manufacturers advise to test water-resistance every time you open the watch, due to a possible gasket shifting. Some service centres are changing gaskets during every service. Watch needs to be serviced by an authorized service centre only, because otherwise, it loses the warranty.

Water-resistance testing methods?

There are two ways of testing water-resistance, "dry" and "wet" test. In the "dry" test, the watch is placed in a chamber and the air-pressure is increased. The machine detects the smallest variation in the case size. If the case expands, even slightly, then the watch is not water resistant.
In the "wet" test, the watch is placed in a chamber which is filled with water. The pressure is increased and if water enters the watch - it is not water resistant.

Can I wear a watch during a bath or shower?

No. Exposure to high temperature, either in the bath or sauna can cause deformation of gaskets and losing the ability to prevent water penetration into the watch.

In addition to high temperatures, what else could compromise water-resistance?

Some chemicals cause gaskets corrosion, heavily chlorinated water may cause problems,  hair sprays and perfumes also. All the above also affect the polish of the watch.