What Do The Ratings on Watches REALLY Mean For Going In The Water July 31, 2015 18:08.
What does water resistant really mean?
Answer: Two-thirds of all watches are designated water resistant.
(Government guidelines prohibit manufacturers from labeling their watches "waterproof.") While you might think a water resistant rating such as "water tested to 50 meters" would mean that someone could safely wear a watch, say, scuba diving, it's really not that simple.
Why? Because testing is done in still water, with a stationary watch. Movement greatly increases pressure, so it's necessary to translate the water resistance ratings into practical guidelines.
The following scenario happens in our store almost every Spring, when people are returning from vacation. A guy comes in with a watch rated for 50 feet that is full of water - heck, he was only swimming in 8 feet of water!!
From the least to the most water resistant, the ratings are as follows:
- Water Resistant - These watches have withstood testing to depths of 24 to 30 meters (100 feet) and will tolerate splashes of water or rain, but should not be worn while bathing, showering, washing dishes, swimming or diving. Watches with this designation will have the words Water Resistant engraved on the case back.
- Water tested to 50 meters (165 feet) - Okay for showering, bathing, dish washing and swimming in shallow water. Not while snorkeling or scuba diving. The designation engraved on the case back will be "Water Resistant 5 BAR" (BAR is a European equivalent of the international measurement ATM, or "atmospheres." To calculate the water-tested depth in meters, multiply the BAR number by 10.)
- Water tested to 100 meters (330 feet) - These watches are suitable for swimming and snorkeling, but not scuba diving. The case back designation will read "Water Resistant 10 BAR".
- Water-tested to 150 meters (500 feet) - These watches can be worn for general water sports, including snorkeling. The case back designation is Water Resistant 15 BAR.
- Water tested to 200 meters (660 feet) - These watches can be worn for general water sports, including snorkeling and skin diving (without scuba gear). The case back designation is Water Resistant 20 BAR.
- Diver's 150 meters (500 feet) - Meets ISO standards and is suitable for scuba diving.
- Diver's 200 meters (660 feet) - Diver's watches with the Water Resistant 20 BAR designation on the case back are our most water-resistant models.
Taken from Seiko USA website