Watch Water Resistance 101

It’s over 30 degrees Celsius outside and its time to head to the beach, but what about the watch you are wearing, can it handle a dip in the water? Well it all depends on water resistance of your watch. Before we get started, I must make one thing clear.  There is no such thing as a “water proof” watch.  That term was discarded years ago.  Now watch manufacturers prefer the term “water resistant“, although I must say the Hublot King Power 4000 meter diver comes pretty close to having optimal water resistancy.   Hublot’s Diving Watch can Dive to Depths no man has dived before!
Watches have varying degrees of Water Resistance depending on the efficiency of the gaskets (O-rings made of rubber, nylon or Teflon, which seals the watch where crystal, case back, and crown meet the watch case); quality of sealant as well as the thickness and material of watch case.  A screw in case back and crown also increases water resistance.
When buying a Water Resistant Timepiece take note of the water resistance to see whether it matches your lifestyle.  Below is a water resistance  guideline:

• To describe a watch as water resistant or 2 ATM, it must have a minimum of 20 meters water resistance; however it is advisable at this minimum requirement, water should be entirely avoided.

• 30m or 50m (3 to 5ATM): Minor Splashes.  Okay for fishing and hanging out by the pool. You can wear the watch in the rain, provided it is not a torrential down pour, and you can wash your hands under a faucet.   NOT for swimming and diving.  Many Haute Joillerie watches encrusted with gems are water resistant to 30 or 50 meters.

• 100 meters or 10 ATM, is suitable for swimming and pool diving, but not for serious sea diving or sports where the water pressure can become quite high like in white water rafting or waterfall plunging. 

• At 200 meter  (20 ATM) water resistance, you can do some serious marine sports and competitive swimming and diving from a diving board; however, if the watch is not specifically designed for diving, one should check on whether one can scuba dive with the watch.

• Divers 200m to 300m (20ATM to 30ATM), one can dive with scuba equipment not requiring a Helium Tank.

• Divers 300m + Helium Valve.  Here you are getting into some serious deep water and a Helium Valve ensures the watch will not be damaged as a result of the tiny Helium molecules which sneaked into the watch case while under the water.  The Helium Valve releases these molecules and reduces the pressure within the watch. The helium and hydrogen molecules cause no damage while the watch is at great depths under pressure but as soon as the diver resurfaces, a pressure difference occurs between the trapped gas(es) inside the watch case and the surrounding air. This can cause the crystal to pop off damaging the watch thus the helium valve is a crucial edition to diving watches enabling the diver to release the gas build up and restore equilibrium.

TAKE NOTE:
Although, a watch may be labeled as having a specific water resistancy, the water resistancy can lesson over time as a result of gasket deterioration, especially if the watch has been exposed to salt water or chlorine.  In order to maintain the water resitancy of the watch, it is advisable to get your watch serviced at least once every two years.
By: R. Van Halem