For many watch collectors, the water resistance is one of the most important elements to consider when selecting a new timepiece. The water resistance rating of a watch will affect how and when it can be worn and how much care it will require. Different watches are suited to different lifestyles, and a collector will need to assess how they intend to wear their new watch before selecting an appropriate water resistance rating to search for. Water resistance ratings can be confusing, and often misleading, so if you are searching for some clarity on what the water resistance rating of a watch actually means, keep reading for a guide to watch water resistance.
Watch water resistance refers to how well a watch will cope when it is exposed to water. However, the depth rating that is used to measure water resistance does not refer directly to how deep in the water a watch will be able to go. The depth rating actually signifies the results of a static pressure test that is held in a laboratory. The results of this test have fairly accurate real-life application, but the depth rating does not strictly mean that a watch can safely be worn to that depth.
The water resistance of a watch is normally expressed in metres, bar, or atmospheres. One bar equates to around 10 metres, so it is easy to convert the units. Atmospheres (often shown as ATM) and bar are both units of pressure. They are approximately equal and are often used interchangeably.
ATM means atmospheres and it is basically the same as metres. However, if your watch says 20 metres, this does not mean that a watch can be taken 20 metres below sea level. Despite this being a common misconception, it is simply the number of times the pressure at sea level a watch can endure without letting water in.
You should never wear your watch in the shower. The combination of hot water and soap or shampoo can over time degrade the rubber gaskets that keep your watch's water resistance. This will reduce the water resistance rating of your watch over time and require more frequent watch services.
Water Resistant
If a watch is said to be simply ‘water resistant’, it is likely that it is resistant to very small amounts of water. It will be safe to wear these watches in small rain showers as they should be able to withstand accidental splashes of water. Watches with this rating should not be submerged in water.
30 metres (3 bar/3ATM)
A watch with a water resistance rating of up to 30 metres (3 bar/3ATM) can withstand small accidental splashes. It will be very similar to a watch that is said to be simply ‘water resistant’.
50 metres (5 bar/5ATM)
A water resistance rating of 50 metres means that the watch will be resilient to splashes, showers and some light swimming. It is advisable to avoid sudden pressure changes, so watches with this rating should not be worn for any kind of diving activities.
100 metres (10 bar/10ATM)
Watches that are listed as having a water resistance rating of up to 100 metres are suitable for swimming and snorkelling. A watch with this rating will be very resilient to daily life and can be worn for showering and handwashing without any fear of damaging the watch.
200 metres (20 bar/20ATM)
This is considered a rather high water resistance rating for a watch. Timepieces with a water resistance rating of up to 20 bar can be worn for swimming, high-impact waters sports and scuba diving. A watch with this rating would be perfect for avid swimmers and surfers.
300 metres (30 bar/30ATM)
A watch that is said to be water resistant up to 300 metres can be worn for all high-impact water sports. It could also be worn for scuba diving and saturation diving. This high level of water resistance is perfect for someone who loves water-based adventure with their wristwatch as a reliable companion.
