Many watchmakers consider water resistance as an essential characteristic of the timepiece, based on the industry’s standards that have become the basis of most watch manufacturers.

The first standard is known as the ISO 2281 or the Water-Resistant Watches Standard, created by the International Organization for Standardization (ISO). First identified in 1990 as ISO 2281:1990, which introduced the term water-resistant watches instead of ‘waterproof.’

For diving watches, a different ISO is responsible for its regulation. The ISO 6425 oversees the standard set for the manufacturing of diving watches. Further defining dive timepieces as watches that can resist pressure when diving in water at depths of at least 100 meters and possessing a system to control the time.

Water-resistant watches are suitable for daily activities and should be perfect for swimming. A test is completed under a different environment with controlled variables. Depending on the indicated water resistance mark on the watch, the timepiece should be ideally used underwater based on its ATM measurement.

This test is mostly conducted in a laboratory set-up, subjected to controlled factors where pressure is slowly applied to the timepiece‘ cases then reduce it in the same manner.

During a watch resistance test, the timepiece is subject to the pressure of water on the machine (such as Bergeon BG5555 or similar device used watch  factories). It is essential to make sure that all the gaskets are sealed.

In general, a watch with 3 ATM is suitable for use when taking a shower or doing the dishes but never while swimming, snorkeling, or diving. Such activities are perfect for those watches with 50 ATM, except snorkeling and diving. Otherwise, it is better to use a watch with at least 20 ATM resistance if you want to do diving.