Water Resistant vs Waterproof Watches - Is there a difference?

Last Updated: January 15, 2019
Written by Andre Wallace

The terms “water resistant” and “waterproof” get thrown around a lot in the watch world. But what do they actually mean and is there a difference?

Let’s start with a little mythbusting.

“Waterproof watch” is a lie

Let’s start by just removing “waterproof” from our vocabulary. It’s misleading at best and downright dangerous at worst. Waterproof implies that water cannot enter the watch. This is false. All watches will inevitably give in under enough pressure and let water in.

It doesn’t matter if it’s a Rolex Submariner or another well engineered timepiece made specifically for diving, all watches have their limitations as we can’t avoid the general laws of physics.

Waterproof is just marketing jargon

There is no meaning behind the usage of “waterproof”. If you see a watch manufacturer still using this term, it’s time to become suspicious of their marketing material and potentially question the quality of the watch itself. Don’t be fooled by marketing gimmicks.

Most watch manufacturers selling into English speaking countries switched from using waterproof to water resistant many years ago (around 1970). This was partly due to the misleading nature of the term “waterproof”. Consumer protection legislation in these countries would probably have an issue with the term waterproof too – as it could easily be argued a watch marketed as “water proof” would not be fit for purpose if any water did get inside.

Water resistant is now the standard

Most watch manufacturers have now abandoned waterproof for the more accurate term “water resistant”. This term actually has meaning, as watches claiming to be water resistant to a certain depth need to comply with specific testing of international standards. There are two different standards commonly used by watch manufacturers;

ISO 2281 – Basic standard for watch water resistance

ISO 2281 (now superseded by ISO 22810) is the standard manufacturers need to comply with if they want to legally claim their watch is water resistant. The compliance process is thorough, including tests for the following:

  • Water resistance: Watch is placed in 10cm of water for 1 hour.
  • Moving parts resistance: Buttons are pressed in 10cm of water for 10 mins.
  • Condensation: Watch is heated between 40 °C and 45 °C and a drop of water placed on the glass.
  • Temperature: Watch is placed in water of varying temperatures (40 °C to 20 °C and back to 40 °C)
  • Pressure: Watch is placed in a vessel at pressure of rating for 10 mins.

ISO 6425 divers’ watches standard

Dive watches are regulated by a more comprehensive standard, the ISO 6425. This standard applies to watches rated at 100m or more water resistance. A big difference in the testing procedure is that each watch certified to ISO 6425 must be tested, not just randomised testing like the ISO 2281. This introduces a significant cost burden to the manufacturers which is ultimately passed onto the consumer. This has resulted in not all manufacturers opting to certify diving watches to ISO 6425.

Tests for ISO 6425 divers’ watch are significantly more thorough than the general 2281. These tests include:

  • Under water reliability Watch is placed in 30cm of water for 50 hours between 18°C to 25°C.
  • Crowns and buttons: Watch is placed under 125% of rated pressure for 10 mins and the crown and buttons are pressed.
  • Condensation: Watch is heated between 40 °C and 45 °C and a drop of water placed on the glass. Condensation tests are applied before and after the above two tests (Reliability + Crowns and Buttons)
  • Thermal shock: Watch is placed in 30cm of water for 10 mins of varying temperatures (40°C to 5°C and back to 40°C)
  • Pressure: Watch is placed in a vessel at 125% of pressure rating for 2 hours. Pressure reduced by 0.3bar and held for 1 hour.

In addition to the above, there are more requirements for mechanical watches covering bezel operation and visibility, readability at 25m, luminosity in total darkness, magnetic resistance, shock resistance, salt water resistance and strap durability. Mixed-gas diving watches also have special provisions.

It’s important to recognise the limitations of these lab tests on real-world diving conditions. Tests done under controlled lab environments face very different challenges when released into the wild world of diving where the watch will be truly tested.

Water resistance classifications – what the rating really means

Think you can go diving with your 50m water resistance watch? Think again. You’ll destroy your watch. The following table shows what each water resistance rating really means:

Rating (m)Rating (bar/atm) Suitable activities
Water resistant 30m3Resistant to light splashes and rain. General everyday use but keep out of any water related activity, including swimming and showering.
Water resistant 50m 5Heavier rain and more daily activities. You can submerge the watch underwater, but still wouldn't recommend swimming, showering and definitely no diving or pushing buttons underwater.
Water resistant 100m10Most water based activities. Swimming, surfing, snorkelling but NOT diving.
Water resistant 200m20Professional marine sports such as yachting, snorkelling and skin diving. But, still no scuba diving yet.
Diver's 100m10You can safely dive with this watch.
Diver's 200m20Scuba diving, but not mixed gas diving.
Divers 300m30Scuba diving but not mixed-gas diving.
Divers 300m for mixed-gas diving30Scuba diving, including mixed-gas diving

Water resistance FAQs

Water resistance can be a tricky subject, so we’ve pulled together the following FAQs.

Can I shower with my watch?

You may have noticed that we didn’t recommend showering as an activity for any watch, regardless of its resistance rating. This is because we don’t recommend showering with any watch as it will shorten its lifespan. Water, soap, shampoo and steam are natural enemies of internal watch components.

What stops water from entering my watch?

Rubber seals and gaskets provide the main barrier for water entering a watch. These do get dry over time and can stop providing an effective seal. We generally recommend having your seals checked and lubricated once every year for peace of mind.

Can I push the buttons under water?

Generally, no. Each button requires another seal, introducing another point of failure where water can enter. Using these buttons underwater will significantly increase the chance of failure. This is especially true of chronograph watches as they have more buttons/points of weakness.

There’s fog inside my watch. Is my watch doomed?

Not necessarily. Condensation generally forms when moving from a cold temperature to a warmer temperature. Water creeps in via air particles when it’s cold, and then liquify when it warms up. If it’s just a few little drops, it may very well go away on its own in a few days, but it’s still worth getting your seals checked.

Does age matter?

Absolutely. The older the watch, the greater the chance a seal is weak. Please don’t go diving with a vintage watch you haven’t had checked in a few years. This is likely to end in tears.

What do bar and atmosphere mean?

These are direct measures of pressure used by the watch industry. Bar and atmosphere (atm) are interchangeable.

Can I get my leather strap wet?

Nope. Don’t do this. Leather will stretch and warp when subjected to water, soap and other liquids. If you do get some water on it wipe it off – and don’t stress too much. Just don’t go swimming or showering with it.

Have any other water related watch questions? Please let us know in the comments below and we’ll answer them.

2 comments on “Water Resistant vs Waterproof Watches - Is there a difference?”

  1. Hey! Loved your article, especially how you touched on the ISO 6425 rating. People don't realize that this is important. They see that their watch is resistant up to a 100 m, then wreck it after diving with it on!

    1. Thanks Theodore. I've also had a cheap diver spring a leak while snorkeling at minimum pressure. It sucks, but it's always a small risk when water is involved. Happy diving!

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