The Unsinkable Question Of Water Resistance

Yet another look at one of watchmaking's most talked-about numbers.

688, baby.

The launch of the latest entry into the integrated bracelet sports watch scene, the Tambour (which is just called the Tambour) from Louis Vuitton, was accompanied by a small hiccup in the press release, which said initially that the water resistance of the watch was 30 meters, or 3 bar, or 300,000 Pa. (The pascal, which is, confusingly, not capitalized if you mean the Standard International Unit of pressure but is capitalized if you use the abbreviation, is named for Blaise Pascal, who died at the age of 39 in 1662, exactly three hundred years before I was born, although I, alas, do not have an SI unit named after me and never will unless they develop a Standard International Unit of Dork. I live in hope.) Air pressure at sea level is one bar, or 100,000 Pa more or less, or about 14.7 pounds per square inch.

The water resistance of the watch is actually fifty meters, not thirty, and when this correction was disseminated, the entire watch internet breathed a collective sigh of relief.

Double Standards: Dive Watches And Water Resistant Watches

For many years I have been what I like to think of as a voice of reason crying in the wilderness of depth rating subjectivity, enjoining all and sundry to, instead of consulting intuition, consult reason, or at least look at the international standard for water resistant watches, ISO 22810.2010, which is the 2010 revision of ISO 2281.1990, which was released in, you guessed, 1990. The standard was reviewed and confirmed as current in 2021, so we may take it to apply to any and all watches in countries which adhere in general to the standard, manufactured since 2010, which is already so long ago that I cannot bear to think of the time that has passed, and how far downhill we have come, but that is another story.

Like everything else involved with watches, water resistance is an emotional subject with a lot of historical baggage. For our purposes it is fun to note that while brands liked to boast that their watches were waterproof for many years, eventually the Federal Trade Commission here in the USA got into the act, and said that unqualified absolutes do not serve the interests of the general public. Now manufacturers are enjoined to say “water resistant” instead, with a number that tells you just how far under water you can go before you should start to worry.

The revision to the standard, to make a long story short, tells manufacturers to take reasonable steps to make sure that if it says 30M on the dial, the watch can actually be taken to 30 meters under water without risk. This has not stopped watch enthusiasts from saying that they would no more wear a 30M water resistant watch to go swimming, or take a shower, or even watch The Hunt For Red October, than they would wear an Invicta (who make a surprisingly solid watch but that’s another story) but oddly enough the brands seem to have taken notice of the now-not-so-new standard and its most current revision. You may think that it would be as much of a crime against basic human decency to wear a 30M/3 bar/300,000 Pa watch while swimming, as it would be to drink a fine and powerful Chateau Lafitte with an equally fine but rather delicate filet of sole Meunière, but hey, let’s see what the brands say.

Hey, Let’s See What The Brands Say

Here is Omega’s guidance on what you can and should be able to do with an Omega 30M water resistant watch:

“All current OMEGA watches are water resistant to the depth defined by the model specifications, provided that the water resistant components are intact. This means that an OMEGA watch that is water resistant to 30 metres can be worn for swimming (with vigorous movement) at depths of up to 30 metres [sic] underwater for extended periods without restriction … we would like to emphasize that the water resistance of a watch is ensured by gaskets placed between the crown, the pushers, the crystal, and the watch case. These gaskets deteriorate over time under the influence of external factors such as temperature variations, pollution or chemicals and must be regularly replaced to guarantee the water resistance of the watch.”

Swimming with vigorous movements at depths of up to 30 meters – not exactly the shower-at-your-own-risk rating that you might think. But what do the folks at Seiko say?

Well, there is this handy little chart but their guidance is less bold than Omega’s; for 30M resistance Seiko says, that you are OK for “accidental splashes and contact with rain,” but if you want to use your watch while “swimming, yachting, or taking a shower” go for 50M/5 bar just to be on the safe side. (What the heck is “yachting?”)

Rolex doesn’t get into what the individual categories of depth ratings mean in terms of practical use, as far as I can tell, or at least there is no particular chart anywhere on their website that gives recommendations for different depth ratings. The least water-resistant watch in the Rolex catalogue right now is the new 1908 automatic, and here, interestingly enough, Rolex actually ignores the usual practice of avoiding “waterproof,” saying the watch is “waterproof to 50 meters/165 feet.” I have gotten the impression over the years that Rolex, like Omega, means what it says when it comes to water resistance – Jason Heaton over at Swimpruf dove with marine biologist and conservationist Sylvia Earle in 2017, and the then-82-year old scientist was diving with a 50M water resistant vintage gold Datejust.

Citizen has been in the water resistant watch business ever since the launch of the Parawater in 1959, and has made a number of breakthrough dive watches over the years, including the cult-classic Aqualand. Citizen’s recommendation for a 30M resistant watch says, “While this watch can withstand moisture such as the perspiration produced in everyday activities and splashing from face washing or rainfall, it should not be used in conditions where there are significant changes in water pressure.” For 50M water resistance, Citizen says, “Recommended for people engaged in work that involves frequent contact with water, aquatic sports or similar activities. Note that it is not suitable for free diving,” and somewhat confusingly, this seems to overlap at least to some degree the recommendation for 100M rated watches. For these, Citizen recommends, “Safe for use by people engaged in work that involves frequent contact with water (fishing, farming, car washing, catering, etc.) or in free diving or aquatic sports (swimming, yachting, fishing, etc.). The push buttons cannot be used under water.”

These recommendations are all for water resistance ratings for non-diver’s watches, which are regulated by the much more specific, and more strict standard, ISO 6425. The testing frequency and severity is very different for dive watches so when you’re talking about water resistance you have to make sure you are not comparing apples and oranges. A 100M water resistant dive watch (and 100M is the minimum depth rating for a dive watch, per ISO 6425) or indeed any “dive watch” is required to be tested to 125% pressure over the depth rating in water for two hours, and there are a battery of other tests as well.

So What’s The Deal

A “water resistant” watch under the standard ISO 22810.2010 does not have to be subject to the same testing regimen as a dive watch under the standard ISO 6425. ISO 22810 does not define a minimum depth rating for water resistance. Instead, it presents testing criteria for the widest possible practical range for non-dive watches, and also makes it the manufacturer's responsibility for stating "warranty conditions and precautions to be taken to maintain the quality of the watch over an extended period of time."

The take home for me at this point, is that the standard for “water resistant” watches” leaves it up to the manufacturer and you should probably just follow the manufacturer’s guidelines. The latest Patek Calatrava ref. 6119 is 30M water resistant and if you look at the watch, which is a thin gold dress watch on a leather strap, there is nothing that would make you think you should wear this watch in the shower, let alone whilst “yachting” whatever that means. The hand-wound Vacheron Traditionelle reference 82172/000R-9382 is likewise 30M water resistant but as with the Patek, if you think that this watch on a leather strap is something you are entitled to feel it is OK to take into the hot tub (or “yachting,” whatever that means) then you may have bigger cognitive problems.

All that said, once you hit 50M water resistance things get more robust in general, and at 100M even for a non-dive watch, you can probably swim, shower, go “yachting” (whatever that is) and in general live the Life Aquatic to your heart’s content. And any watch that is billed as a dive watch, which all have to be rated to 100M anyway, are certainly, and I feel I can say this without reservation, good to go to 100M (and probably too 125% of that as well).

The last question is whether or not 50M water resistance is adequate for a modern sports watch, which in the context of the Louis Vuitton Tambour is where the whole thing came up. Of all the guidance documents I’ve looked at there is nothing to make me think that a modern, ISO ISO 22810.2010-compliant watch – and again, not a dive watch – would be in trouble in any situation short of repeated use in scuba diving and, of course, recreational air diving takes place at maximum depths of 30-40 meters/100-130 feet anyway. It seems to me that if you are uncomfortable swimming or showering or “yachting” (whatever that could possibly mean) with a 50M water resistant watch, you are appealing more to a desire to have a technical product over-spec’d rather than to actual practical necessity. But the emotional appeal of over-spec’d watches is why we have 1000M water resistant dive watches.

My guidance for different water resistance ratings:

• Not water resistant: no hand-washing or splashing and don’t get into the tub in your hotel with your rubber ducky without taking off your vintage watch with no gaskets of any kind, but you knew that anyway. Wear while wandering through a city at night in a pouring rain while reflecting that better men than you have died in pointless causes, and that Roddy Martindale is an ass.

• 30M water resistant: disrobe, before getting in the shower; glance nervously down at your wrist and realize that even if the watch could take it, it would cost so much money to replace the strap. OK for situations where you may after a roisterous dinner with comrades run the risk of spilling a glass of Pouilly-Fuisse over your wrist. Also probably OK for when you are picked up and tossed into the deep end of the pool in Vegas at your bachelor/bachelorette party.

• 50M water resistant: Swim as liked. Hot tub as liked. Also OK to wear while watching any war movie in which the protagonist is the commander of a surface vessel whipped white with foam while crossing contested waters under the constant threat of being torpedoed. Do not wear while watching any movie where the hero is a submarine commander or becomes one by default. Also OK for bathing the kids, washing the dishes, and beating on, boats against the current, borne back ceaselessly into the past.

• 100M water resistant: Minimum water resistance for watching submarine movies without feeling woefully inadequate and indeed like the bad guy. Wear while watching The Hunt For Red October; Run Silent, Run Deep; The Enemy Below. Minimum depth rating for finishing the movie, looking out your living room window with a steely glance into the Sun westering in a blood-tinged gloom, and reflecting that while there are no good wars, there are always good men.

• 1000M Water Resistant, ISO 6425 compliant dive watch: Minimum depth rating for watching Das Boot.