Demistifying Water Resistance
As I’m sure you can imagine, water is a wrist watch’s worst nightmare. The words ‘water-resistance’ are thrown around a lot when you’re looking for a prospective shiny new wrist watch! But, we’re here to tell you that you don’t have to be a keen diver to understand the difference in levels of water-resistance, and how best to care for watches when they do come into contact with water.
For some watch brands, even the tiniest drop of H20 in the wrong place can cause catastrophic damage. So, we’ve demystified the different scales you’ll often see describing a watch’s water resistance, and also given tips on how to protect and maintain your watch to ensure it keeps ticking!
What Does Water-Resistance Actually Mean?
Here’s the definition of water resistance; water resistance is the measure of how much pressure a watch can withstand underwater. Often denoted in units of bar, atm, or depth (m), the number given to a watch is the unit of pressure a watch can withstand in a static pressure test under laboratory conditions that simulates water pressure.
What is the difference between ‘bar’ and ‘atm’?
The atm unit corresponds to pressure at sea level which is known internationally as an average because the pressure at sea level changes. A bar is another unit of measurement belonging to the metric system. All you need to remember is that: 1 bar = 0.98 atm = 10m
One of these water-resistance units will usually be stamped on the back of your watch case or written on the face. To help make reading these units simpler, we’ve outlined the different levels you’ll see below, and what activities each one is most suitable for.
Watch water resistance table
| Water resistance rating | Accidental splashing from washing hands, rain etc. | Showering or swimming | Swimming or snorkelling | Swimming, snorkelling, skin diving | Scuba diving |
|---|---|---|---|---|---|
| 'Water Resistant' or 30m (3bar) | ✔ | ✗ | ✗ | ✗ | ✗ |
| 50m (5 bar) | ✔ | ✔ | ✗ | ✗ | ✗ |
| 100m (10 bar) | ✔ | ✔ | ✔ | ✗ | ✗ |
| 300m (30 bar) | ✔ | ✔ | ✔ | ✔ | ✗ |
| 500m (50 bar) | ✔ | ✔ | ✔ | ✔ | ✔ |
Wearing a watch will affect its resistance
When being worn, a watch will almost always be in motion on your wrist. Believe it or not, this contributes to the pressure exerted on a watch so bear this in mind if you’re serious about the amount of pressure your watch needs to withstand.
For example, a typical watch could be marked with a water resistance depth of 30 metres. So, naturally you might assume that jumping off the middle or top plank of an average diving board would be fine. However, there’s quite a high chance that the pressure change that the watch would be subject to when you hit the water would push the capabilities of the gaskets to their limits, and cause the watch to start leaking.
How is a watch made waterproof?
To protect the inner workings of a watch from the outside elements, a rubber or silicon hoop, called a ‘gasket’ is used as a seal. The gaskets sit inside the case and crystal, and around the stem, crown, pushers and correctors (all the pieces that are exposed), forming a seal around the important mechanisms within.
Over time, and after repeated exposure to water, the gaskets will begin to dry out and lose their elasticity, which is when the water-resistance will begin to decrease - this is why regular testing is crucial to your watch maintenance, as gaskets can be checked and replaced easily before the damage is done.
What’s The Difference Between Waterproof and Water-resistant?
You will rarely see a watch described as ‘waterproof’, as this implies that under no circumstance will water be able to permeate. Modern technology can mean that watches can withstand more and more pressure while still operating, however there will always be a limit to its resistance, and even the tiniest gap in the gasket seal can cause damage. All watches are therefore technically only water-resistant, never truly waterproof.
Maintaining a water-resistant watch
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Get in touch
Simon Porter
Director, James Porter & Son
Simon is the 5th generation Porter to look after the day to day running of the James Porter & Son store since its inception in 1858. Working alongside his father since 1995 and eventually taking over the reins full time in 2007.
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