The use of “waterproof” was replaced sometime back in the 60‘s with “water resistant”. This was do to the government deciding that no watch is ever waterproof. Overtime, gaskets and seals can become less effective do to environmental exposers and aging. Therefore, it was decided watches can not be deemed “waterproof” by definition.
Water Resistance Guide
- 30m or 99 feet - light water contact, rain, splashing of water, not for swimming or immersion
- 50m or 165 feet - shallow water or pools, not recommended for any type of diving
- 100m or 330 feet - general swimming, snorkeling, showering, not recommended for scuba
- 200m or 660 feet - water sports, skin diving, scuba diving
- 500m or 1650 feet - all the above and deep diving
There are still several things to take into consideration before exposing your favorite watch to water. A watch rated with 50m of water resistance does not take into consideration other key factors. For example, diving off of a high dive into pool applies a sudden impact, applying more force/pressure on the watch. Though, the watch is not going 165 feet deep, the impact pressure might be more than the actual pressure at 165 feet of water, compromising the watches rating. W&R recommends that any type of water submersion be done with a watch with at least 100m of water resistance and a screw down crown.
In general, there are variables that can effect the degree of water resistance, such as sudden impact (diving, water skiing), rapid change in pressure, extreme temperature change (whirlpool), and age of seals and gaskets. It would not be a bad idea to have your watches seals/gaskets looked at by a trusted watch maker every three years, especially if the watch is regularly exposed water.