Water resistance

Water Resistant

Splash proof only.

30 meters/3 ATM/3 BAR

Resistant to small amounts of water, like splashing from washing your hands.

50 meters/5 ATM/5 BAR

Suitable for showering.

100 meters/ 10 ATM/ 10 BAR

Suitable for swimming and snorkeling.

200 meters/ 20 ATM (plus)/ 20 BAR

Suitable for standard scuba diving.

1000 meters/ 100 ATM/ 100 BAR

Suitable for deep sea diving.

IP67/IP68

Water resistance rating for electronical equipmenty (e.g. smartwatches and wearables)

 

The definition of water resistance

Water resistance is shown with the terms Bar (air pressure), ATM (atmosphere) or meter. When it is indicated whether a watch is waterproof, this is often indicated in meters. The higher the number of meters the "deeper" the watch is waterproof. But do not take the number of meters literally! In fact, it indicates how many meters pressure - similar to the pressure of still water with no movement - the watch can withstand. A watch with a water resistance of 50 meters is not suitable for swimming (but you can take a shower wearing it).

A watch which indicates that it is 'waterproof', without any depth or pressure indication is splash proof only. If the watch has become thoroughly wet, it must be dried as soon as possible and be taken to a watchmaker for a check up.

Unique features of water resistant (diving) watches

To create water resistant watches, in general, a pressure base with a rubber 'O'-ring is used. To withstand a higher (water) pressure, the back of the watch is screwed to the case. The watch crown and pushers are equipped with rubber washers and thread which should all be tightened to the case (screwed crown) after use. Watches suitable for scuba diving have a helium (vent) valve.

Dive watches are often equipped with a movable bezel to assist in timing a dive. This bezel is purposely unidirectional to avoid unintentional resetting of the left over diving time.

A dive watch strap is usually made of rubber, resin or stainless steel. The clasp is often equipped with an extender enabling the watch to be worn over a wetsuit.

Maintenance

Because water resistance is measured in units of pressure temperature differences should also be taken into account. Because the different components and materials of the watch extend and shrink at different rates, a sudden drop in temperature can cause the components to warp slightly, resulting in a diminished water resistance and leakage.
The most common cause is when the watch is suddenly gets cooled down after being out in the sun. Extra caution is advised with watches water resistant to 3, 5 and 10 bar.

It is also advised to be careful with hot water. Hot water from the tap, bath or sauna can also cause pressure differences resulting in a diminished water resistance and damage the movement.

It is important to clean your water resistant watch (from 5 atm upwards) with fresh water after every visit to the beach. Salt water and sand can corrode the metal and cause friction in the bezel.

Important: Have your watch tested for water resistance by a watchmaker, each time the watch case has been opened, e.g. for changing the battery.

If despite all precautions, you suspect the water resistance of your watch has been compromised, you can just test this by placing an ice cube on the watch crystal for a few minutes. If the crystal fogs up on the inside, it means the watch contains some damp. Always take the watch to a licenced watchmaker for repairs.

Water resistance of smartwatches and wearables

Electronical equipment such as smarwatches and wearables have their own standard of water resistance, called the International Protection Rating or IP-code.

For more information read our article about IP-ratings here.