Smartwatch water resistance: The technology demystified

Are you the kind of person who removes their watch before doing the dishes or washing your hands? Even when you’re wearing an advanced smartwatch that claims to be waterproof or water-resistant? If so, that’s an old tape whirring in your brain, likely derived from the childhood experience of trashing the wristwatch your parents gave you by forgetting to remove it before plunging your hands into a wet sink or jumping into a swimming pool. Those days are long gone, but old habits are sticky.

Today, the vast majority of smartwatches are built with some degree of water resistance, so that relatively benign contact with moisture will not be fatal to your expensive timepiece. Here are the ratings and specifications you should look for, whether you wear your watch while operating a gardening hose or scuba diving.

Water-resistant vs. waterproof

A water-resistant product is not waterproof, and right now there is no such thing as a waterproof watch. Water-resistant is the lowest level of protection, meaning that the item is designed to make it difficult — but not impossible — for water to seep through. Waterproof means the item is impervious to water no matter how long it is submerged. A watch may also be advertised as “sweatproof” but that is another measure entirely, as sweat has corrosive chemistry — water, uric acid, sodium chloride, and lactic acid — that is much more damaging to electronic equipment than plain water.

For smartwatches, waterproof actually means water-resistant as specified by the manufacturer under specified test conditions. Water resistance is measured by IP (Ingress Protection) or ATM (Atmospheres ) ratings. It’s generally either one or the other for any given item.

Water resistance is not permanent and can diminish over time and under certain conditions. Dropping your watch so that it absorbs impact is generally bad for withstanding water over time. So is exposure to substances like soap, solvents, sunscreen, hand lotions, insect repellants, or wearing your watch in a sauna or steam room.

If you’re shopping for a smartwatch or fitness tracker for use while freestyle swimming, make sure to check the company website and read the fine print in the manual. That’s where you’ll find all relevant use parameters for the product. Search for “water-resistant” in the documentation to jump right to the critical fine print. Ignore the marketing and ad copy and especially any images associated with the product’s use around water, as it can be misleading.

IP rating

The IP stands for Ingress Protection or International Protection, defined as the water and dust resistance for electronics. This rating is published by the International Electrotechnical Commission (IEC) — an equivalent European standard is EN 60529. A rating of IP followed by X and a number means the item has been tested in water only. IP followed by two numbers means testing has been completed for dust/dirt resistance (first number) and water resistance (second number). When IP is followed by both a number and an X, that means it’s been tested for dust resistance only, and not for water resistance. Here’s the breakdown.

  • ipx0: Not protected
  • ipx2: Dripping water when tilted up to 15 degrees
  • ipx3: Spraying water
  • ipx4: Slashing water
  • ipx5: Water jets
  • ipx6: Powerful water jets
  • ipx7: Temporary immersion in water up to 1 m — about 3.3 feet of static water for up to 30 minutes.
  • ipx8: Continuous immersion in water beyond 1 m as specified by the manufacturer. This should ring bells for buyers because that means the manufacturer of your watch is setting the standard of how it performs beyond the IPX7 level.
  • ipx9: Protected against high pressure and temperature water jets.

A separate Dive rating complies with EN13319, and allows for the usual splashes, rain, showering, swimming, and diving into water, as well as snorkeling, high-speed watersports, and scuba diving.

ATM rating

Atmospheres ratings are somewhat more popular for smaller wearables like smartwatches and fitness trackers, though these too now can use IP ratings, which used to be primarily for larger items such as headphones, smartphones, and speakers. Atmospheres map to pressure testing measurements, which are then translated into water depth to determine how much the device can take. For example, a smartwatch that carries a 5ATM rating means it can withstand depth pressure of 50 meters. Water pressure can vary, particularly when swimming, so a smartwatch or fitness tracker can carry an ATM rating, even though it still might not be safe for immersing in water. Devices with a 1ATM or 3ATM rating should not be used in any swimming environment.

  • 1 ATM: Depth of 10 meters (33 feet) — Avoid contact with water.
  • 3 ATM: Depth of 30 meters (98 feet) — You can get caught in the rain or wash your hands, protects against splashes.
  • 5 ATM: Depth of 50 meters (164 feet) — allows for limited submerged in water, for swimming in a pool.
  • 10 ATM: Depth of 100 meters (328 feet) — allows for extended submersion, such as snorkeling in the ocean.
  • 20 ATM: Depth of 200 meters (656 feet) — allows for high impact water sports like surfing and jet skiing.

MIL-STD-810G rugged ratings

The most common standard for rugged devices is MIL-STD-810G, an overarching classification with many durability subcategories, like protection against drops and impact. It relies on a battery of tests that simulate various environmental conditions, such as shock and vibration. For example, the MIL-STD-810G’s shock test requires 26 drops across five devices onto two inches of plywood on concrete. While product manufacturers must meet those specifications to sell to the military, consumer products like smartwatches can tailor or abbreviate the tests they perform. For non-military purposes, the standard describes 28 variable tests that engineers and designers can tailor and select to “generate the most relevant test data possible.”  Here are just a few examples.

  • 500.5: Low-pressure altitude
  • 501.5: High temperature
  • 502.5: Low temperature
  • 503.5: Temperature shock
  • 506.5: Rain
  • 507.5: Humidity
  • 510.5: Sand and dust
  • 512.5: Immersion
  • 514.6: Vibration
  • 516.6: Shock

Apple Watch

apple-watch-series-5
Andy Boxall/DigitalTrends

Apple gives a specific lowdown on the water resistance features of all of its watch models. The first-generation Apple Watch has a water resistance rating of IPX7 under IEC standard 60529. Apple Watch Series 2 and later have a water resistance rating of 50 meters under ISO standard 22810:2010.

Classic Buckle, Leather Loop, Modern Buckle, Milanese, and Link Bracelet Bands are not water-resistant. You can wear your watch while exercising, washing your hands, or walking in the rain. Series 2 or later is OK for shallow water swimming in a pool or ocean, but not for scuba diving, water skiing, or other activities involving high-velocity water or deep submersion. Apple says the watch should be cleaned with fresh water and dried with a lint free-cloth if it touches anything that’s not fresh water.

Samsung Galaxy Watch

Samsung Galaxy Watch
Samsung

According to Samsung, the Galaxy Watch passed military specification MIL-STD-810G testing against 10 specific conditions, including drops from 4.9 feet, extreme temperatures, dust, shock/vibration, and low pressure/high altitude. The Galaxy Watches are also water-resistant up to 50 meters per ISO standard 22810:2010. They are not intended for scuba diving. Samsung warns buyers to avoid excessive, sudden temperature changes and high-velocity activities. And the remedy for watches connecting with anything but fresh water is similar to Apple’s solution of rinsing in fresh water and drying after use in seawater or chlorinated water.

Garmin

Garmin Fenix 6 Pro

Garmin makes a variety of sports watches with a range of specifications. The Descent Mk1 is specced to 10 ATM and Dive (Designed to comply with EN13319), which means that you can go scuba diving with this watch. The new Garmin Swim 2 is rated 5ATM, while the Fenix 6S Pro is rated 10ATM and can measure your underwater wrist-based heart rate. The Vivoactive 4 series has a 5ATM rating.

Bottom line

Getting the best performance from your smartwatch — and keeping it safe in the process — means knowing what you intend to use it for and making sure that the product is up to the task. When you’re buying a smartwatch, do not rely on ratings or marketing copy, because the meaning of ratings can vary according to what the manufacturer tests and the testing protocols. Instead, go by the manufacturer’s product guidelines of what kind of immersion the product can withstand.

Assume that any waterproof claim is limited to less than 1 meter (3 feet) unless otherwise stated. Also assume that buttons, ports, and dials cannot be used while the device is exposed to water. In all other instances where you don’t know for sure, use your common sense to protect your valuable device and err on the side of caution. If an activity sounds dangerous to your device, it probably is.

Don’t forget about your watch band. Metal or leather in water is a definite no-no, though silicone or nylon sport bands should stand up to your swim just fine. While manufacturers test under lab conditions, the real world often presents tougher challenges to your smartwatch, and no device will stand up to sustained abuse, regardless of how rugged it’s built to be.

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