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How are watches water resistant?

Have you noticed how most watches claim they are “water resistant” to a given depth. This may raise the question of “how are watches able to be water resistant?”, well fear not because this week that’s exactly what we’re gonna be answering. Let’s get straight into it.

So first things first, watch manufacturers must use the phrase “water resistant” instead of “waterproof” due to legislation which was introduced in the 1960s by the Federal Trade Commission in the USA. The term “waterproof” means “impervious to water” which of course is untrue when a watch is submerged in high pressured waters; it will eventually begin to leak. Because of the misleading advertising, the FTC said that watches must be described as “water resistant” instead. The term “water resistant” means “able to resist the penetration of water to some degree but not entirely” so you can see why the use of this term gives the manufactures a bit more leeway if the watch was to break due to water pressure.

If a watch claims to be water resistant to 100 meters, for example, this means the watch case should not leak if it’s in no more than 100 meters of water. The water resistance depth usually means that the watch will keep out water at the given depth if the watch and the water are both motionless, so keep that in mind as wearing the watch and moving it about adds a fair amount of pressure. This is why its recommended that watches should be worn in depths less than what’s indicated.

So, now onto how that watches are actually able to keep the water out. A water resistant watch will contain a gasket which is basically a rubber seal which prevents water and other contaminants from entering the watch. The gasket will form a water tight seal where the crystal, crown, and case back meet with the watch case. Another important feature is a screw in crown which stops water getting into the watch through the stem hole. A screw in case back can also be used to improve the water resistance of a watch. Under great pressure, watch cases need to be sturdy enough to prevent collapsing which is why stainless steel cases are mainly used for watches which are water resistant to high pressures, as opposed to soft precious metals which would have to be quite thick to withstand the pressure. To add that extra level of water resistance, the watch case would be lined with a sealant.

Despite all of the effort that goes in to making sure your watch is water tight, the water resistance of a watch doesn’t last forever. The water resistant components of the watch can become damaged and less effective over time due to general wear and tear such as: exposure to very high or very low temps, exposure to chemicals, corrosion, not rinsing after being in sea water, or just having lots of use. This is why its recommended that you get the water resistance of your watch tested at least once a year. In the tests your watch will be subjected to both air pressure and water pressure, if there are signs of air or water getting into the watch it will be deemed not water resistant.


Keeping it short and sweet today, but I hope you now have a basic understanding of how watches are able to stay waterproof. Oh, and remember to take care of your watches and get them checked out regularly. Hope you've enjoyed, have a great day :)


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