Feb
20
2010

Is a "50M" watch waterproof to 50 meters?

Photo by lovstromp - CC-BY

Photo by lovstromp - CC-BY

If you just bought a watch rated “50M”, you would be forgiven for assuming that it is waterproof to a depth of 50 meters. So can you go diving with it? No way…

Ratings such as 30M, 50M, 100M and 200M indicate watches that are in some way water resistant, but are unsuitable for scuba diving. If you want to take a watch diving, you absolutely need to get one that is specifically rated for diving.

For most people a rating of 50m will be adequate for recreational swimming, and a rating of 100m will be suitable for other water sports. Here's a more detailed breakdown of what you can do with “water resistant” watches:

Google Wants To Pay You!r>

30M 50M 100M 200M
Perspiring y y y y
Car washing y y y y
Dishwashing y y y y
Walking in the rain y y y y
Showering n y y y
Bathing n y y y
Skiing n y y y
Parachuting n y y y
Swimming in still water n y y y
Fishing n y y y
Snorkeling n n y y
Poolside diving n n y y
Surfing n n y y
Water skiing n n n y
Professional water activities n n n y
High diving n n n y
Deep diving without scuba n n n y
Scuba diving n n n n

Even if you follow this table, you're not supposed to press the buttons while the timepiece is wet. To maintain the water resistance you must avoid taking the watch into saunas or hot tubs, and must have the seal renewed whenever the battery is replaced.

The testing of watches for water resistance is described by ISO standard 2281. The standard only requires that a sample of watches is tested, and the sample is only tested with a static pressure (which explains why you can't actually go diving to 50 metres depth and expect a 50M watch to remain waterproof). Furthermore, not all watch manufacturers use ISO 2281.

zp8497586rq

Related questions:

  • What is tombstoning?What is tombstoning? Tombstoning is a perjorative term coined by the media and the health'n'safety brigade to describe the practice of jumping off high places into water. Others might call it "jumping into […]
  • What are some of the risks of tombstoning?What are some of the risks of tombstoning? "Tombstoning", the practice of jumping from a height into water, is an enjoyable recreational activity. However, it is associated with a steady stream of rescues, injuries and deaths. […]
  • How does a radio-controlled watch (or radio controlled clock) work?How does a radio-controlled watch (or radio controlled clock) work? In many countries of the world you can buy a clock or watch that will always show the correct time to the nearest second, and which never needs to be set. It will even automatically […]
  • How well do solar powered watches work?How well do solar powered watches work? The promise made by a solar powered digital watch is a big one—an end to the need to periodically replace the watch battery. And if the solar powered watch also has radio controlled […]
  • Can you swim through Durdle Door?Can you swim through Durdle Door? Durdle Door is a stunning rock formation near Lulworth Cove in Dorset. The sea has eroded a hole through a line of limestone, forming an arch. The beach at Durdle Door is popular for […]

  Need research? Quezi's researchers can answer your questions at uclue.com

Written by | 8,205 views | Tags: , , , ,

3 Comments

  • larry says:

    Watches, like the one illustrated, only claim “water resistant”, which doesn’t promise “waterproof”.

    I found a watch that is advertised as “waterproof”. The specifications said “submersible 300 m”. Well, anything that sinks is submersible, but on another website it said that the crown screwed down on the case, the only way to assure waterproof.

  • Pippin says:

    I bought a Casio 50M watch 30 years ago. It has never left left my body other to replace the battery. I have scuba dived to 70 feet, shower, swim, sleep, work, …
    I don’t understand your chart above in reference to my watch. I have finally broken the band so many times that the pin portion has broken out. I am going to buy another one.

  • eiffel says:

    I’m glad you have such a great watch! I’ve had a few 50M watches over the years. Some have remained waterproof in the sea while others haven’t. It may depend on how well the seal is seated when the battery is changed, as I had a couple of failures soon after a battery change.

    This water resistance rating scheme is designed by the watch manufacturers themselves. Here’s Casio’s FAQ entry about water resistance ratings.

    My current Casio watch is rated 100M. Interestingly, the back panel claims “Water Resistant 10 BAR”, which is the static pressure at 102 meters below sea level. Of course, dynamic pressures are much higher than static, especially in the surf.

RSS feed for comments on this post.


Privacy Policy | Acknowledgements