You buy a new watch and see that it has 50M written on its dial. Does this mean that you can actually take it 50 meters (~165 feet) below water surface? It would be quite handy, right? Not so fast! You would actually permanently damage your precious time piece.
So how is it that 50M isn't 50 meters? And what should you know about water resistance levels in order to take proper care of your watch?
WHY WHAT'S WRITTEN IS NOT WHAT IT ACTUALLY IS?Let's start by solving the mystery why can't you take the watch to the depth which is written on the dial or back of your watch. The answer lies in a way watches are tested for water resistance. This test is conducted in laboratory where a watch is exposed to a static pressure for a very short period of time at the stated depth.
Here we can already see arising conflicts. When you go for a swim it's not going to be "for a very short period", is it? Also when you swim, you are constantly in motion so it's absolutely opposite from static environment in laboratory. What that does is that it creates much higher pressure because you slice the water with your hands where the watch sits. Especially dangerous moment is when you dive into a pool and your watch meets water surface. Momentary pressure can reach extreme values which will likely lead to a damage to your watch.
So now you know why 50M is not designed to be taken 50 meters underwater for prolonged periods of time. Then why do we need such marking at all? Quite simple: watch industry needs standardized measure in order to be able to classify and compare watches. For educated buyer it also gives a good idea of what he or she is buying.
WHAT IS ISO 22810 AND WHY DOES IT MATTER?
And here's where the ISO 22810 comes in. ISO is actually abbreviation of The International Organization for Standardization. This is a non-government organization based in Switzerland which was found in 1947. Since then it has been setting standards in various industries, including watch industry.
In 1990 a new standard was introduced: ISO 2281:1990. It describes watch water resistance levels. In 2010 it was replaced by ISO 22810:2010 which introduced some changes from the previous standard.
ISO 22810 has a very detailed description of how the test should be done in order to be able to give a watch certain rating but we'll not dive deeper into this complex topic. For us it's important to know that the results are comparable and what those ratings actually mean.
ISO 22810 RATINGS EXPLAINEDIt's time to end the confusion and explain what you can and cannot do with your watch when it comes to water.
⦁ 30M / 3ATM / 3 BAR / 100ft - your watch is only resistant to accidental water splashes, i.e. rain. Anything beyond that can severely damage your watch. It's not designed to withstand showering.
⦁ 50M / 5ATM / 5 BAR / 165ft - this grade is considered great for everyday use. You should be able to take your watch with you when showering but it's not designed for prolonged swimming or snorkeling.
⦁ 100M / 10ATM / 10 BAR / 330ft - now you can actually take your watch underwater without worrying that you'll damage it. It'll withstand swimming and snorkeling.
⦁ 200M / 20ATM / 20 BAR / 660ft - go for watches with this grade if you spend significant time underwater or enjoy high contact water sports. However, these are still not diver's watches and should not be used for diving activities.
⦁ Diver's Watch XXX M / XXX ATM / XXX BAR / XXXft - only the watches that are market "Diver's" and has ISO 6425 standard can be used for diving. XXX will be 100 / 10 / 10 / 330 or higher.
Please note that when in doubt of whether you can do something or not, we advise you to consult with the seller or manufacturer. You know what they say - better safe than sorry!
CRITICAL MISTAKES WHICH ARE OFTEN OVERLOOKED
There are certain things that are a big no-no when it comes to watch water resistance. However, normally you'll never hear anyone talking about them before you actually do one of these things and all of a sudden everyone around you starts asking "didn't you know?". Worst thing about it is that these do not fall under warranty so you'll end up destroying your watch and you'll have to cover repair costs. So what are these sins?
⦁ Steam - technically it's water but it does horrible things to your watch. Never take your watch with you if you love hot steamy shower or enjoy steam rooms.
⦁ Salt - take caution when taking your watch into a sea. Salt causes corrosion and this ultimately leads to deteriorating water resistance level over time and your 100M watch might become not water resistant at all.
⦁ Chemicals - ratings discussed above are water resistance ratings. Various chemicals can easily either visually damage your watch or get through sealants inside of your watch.
⦁ Crown and buttons - for some it may sound trivial and not even worth mentioning but again it's better to be safe than sorry. So here it goes: make sure the crown is pushed in and if it's a screw down crown - screw it down! Also never push buttons on the watch when it's underwater unless it's explicitly allowed in the watch manual.
Hopefully by now you have a strong understanding of how you should treat your watch in order to keep it ticking. Watches are precious items that are willing to serve you for decades if you take good care of them.
And remember the golden rule - when you are not sure, consult! We are always more than happy to answer any of the questions that may arise. Shoot us a message and we'll get back to you: firstname.lastname@example.org