Always ensure the crown is pushed right down and/or screwed tight before entering the water.
Never use a chronograph function while in the water (unless the watch is designed for that purpose) as water could get into the movement.
A watch professional with the appropriate equipment can test a watch's water-resistance.
- The different degrees of water-resistance are:
- Water-resistant: accidental splashing, slight humidity
- Water-resistant to 10 metres: washing hands
- Water-resistant to 30 metres: swimming
- Water-resistant to 50 metres: showering, jumping in the water from a river bank, lake or poolside
- Water-resistant to 100 metres: jumping from a diving board, jet ski, snorkelling
- Water-resistant to 500 metres and more: any water activity
- A water-resistant watch isn't only for divers...
- A hot shower exerts pressure of at least 5 bars (causing the gaskets to dilate because of the heat and pressure of the water)
- Diving from 10 metres exerts 10 bars of pressure
- Falling from a jet ski exerts between 5 and 10 bars
If you notice mist under the crystal or signs of oxidation on the dial, take your watch to a watch professional without delay.
Also read in the Glossary: Water-Resistant