A water-resistance rating describes how a watch case performed in one specific test. It does not promise how the watch will handle hot water, soap or a swim. Read the rating as a set of conditions, check the manual for exceptions, and keep the seals in good shape.
Whether you wear a smartwatch or a fitness tracker, the maker usually prints one of two kinds of marking. They answer different questions, and mixing them up is the most common source of confusion.
The water part of the code covers several situations: drips and spray, jets of water from any direction, temporary immersion in still water, and continuous immersion under conditions the maker sets. Each level is a separate test. A code that covers temporary immersion says nothing about swimming strokes, moving water or pressure at depth.
Treat a pressure rating as a lab result, not as a safe depth for diving. Makers who want a watch used for diving say so and add their own conditions.
Rain, sweat and walking in wet weather.
Washing your hands, as long as you rinse the watch with plain water afterwards.
A shower with plain water at a normal temperature, if the manual allows showering.
Swimming in a pool, if the manual lists swimming as allowed, followed by a rinse.
Hot water, including hot tubs and hot springs. Heat stresses the seals, and a sudden temperature change can draw moisture past them.
Steam, saunas and steam rooms, for the same reasons, plus the humidity.
Sea water and salt water, which leave crystals in buttons and grilles and can corrode metal parts. Rinse with fresh water afterwards.
Soap, shampoo, body wash and lotions. They leave residue that can work under the seals and break down the gasket over time.
Scuba diving, and any water activity with fast-moving water or deep pressure, such as water skiing.
Pressing buttons under water is the riskier action, because each press flexes the seal around it. Avoid unnecessary presses in the water. Never pull or turn the crown when the watch is wet, since that opens the seal you are relying on.
The speaker and microphone holes can hold water after a swim. Many watches have a function that vibrates the speaker to push the water out, so run it after a session. If your watch has no such function, tap it gently with the screen facing down. Never poke the holes with a pin or a tool.
Sudden temperature changes, such as moving from a hot room straight into cold water.
Opening the case, including a battery swap at a shop that does not replace the seals.
Knocks to the case or glass that shift the gasket out of position.
Chemicals left on the gasket, such as soap, sunscreen and chlorine.
Repeated use in conditions the manual excludes.
The rating printed on the box describes the watch when it was new. Check the seals after a drop, after every battery change, and regularly if you swim often. Watch for fogging or moisture under the glass, water that appears after a wash, or a watch that resets or misbehaves after water exposure. Stop using it in water and contact the maker or an authorised service centre.
If the manual says nothing about a condition, assume the watch is not protected against it.
Two rating systems, two different questions
Whether you wear a smartwatch or a fitness tracker, the maker usually prints one of two kinds of marking. They answer different questions, and mixing them up is the most common source of confusion.
Dust and water codes
The first kind is a short code, often starting with the letters IP. It comes from an international standard for enclosures. The first character after the letters rates protection against solid dust, and the second rates protection against water. An X in place of a character means that category was not tested, so assume no protection there.The water part of the code covers several situations: drips and spray, jets of water from any direction, temporary immersion in still water, and continuous immersion under conditions the maker sets. Each level is a separate test. A code that covers temporary immersion says nothing about swimming strokes, moving water or pressure at depth.
Pressure-depth ratings
The second kind is a pressure rating, written as ATM or in metres or feet. It describes how much static water pressure the case withstood in a laboratory, usually in still water. It was never meant to describe real use. A static test does not include water moving against the watch, a jump into a pool, the pressure changes of a dive, or a case that has aged.Treat a pressure rating as a lab result, not as a safe depth for diving. Makers who want a watch used for diving say so and add their own conditions.
Safe and unsafe situations
Most watches with a water rating handle everyday water well, provided the case and seals are in good condition. Use the lists below as a starting point, then defer to the manual, which may be stricter or more permissive. If swimming is your goal, the guide to swimming with a smartwatch covers the rest.Generally fine
Rain, sweat and walking in wet weather.
Washing your hands, as long as you rinse the watch with plain water afterwards.
A shower with plain water at a normal temperature, if the manual allows showering.
Swimming in a pool, if the manual lists swimming as allowed, followed by a rinse.
Not safe unless the manual says otherwise
Hot water, including hot tubs and hot springs. Heat stresses the seals, and a sudden temperature change can draw moisture past them.
Steam, saunas and steam rooms, for the same reasons, plus the humidity.
Sea water and salt water, which leave crystals in buttons and grilles and can corrode metal parts. Rinse with fresh water afterwards.
Soap, shampoo, body wash and lotions. They leave residue that can work under the seals and break down the gasket over time.
Scuba diving, and any water activity with fast-moving water or deep pressure, such as water skiing.
Buttons, the screen and the speaker under water
Water changes how the touch screen and buttons respond. Droplets and wet fingers can register as touches, and a watch may react to water running across the glass. Many watches offer a water lock, or a similar mode, that turns off touch input during a swim or shower. Turn it on before you get wet, and use the physical buttons if you need to pause or switch screens.Pressing buttons under water is the riskier action, because each press flexes the seal around it. Avoid unnecessary presses in the water. Never pull or turn the crown when the watch is wet, since that opens the seal you are relying on.
The speaker and microphone holes can hold water after a swim. Many watches have a function that vibrates the speaker to push the water out, so run it after a session. If your watch has no such function, tap it gently with the screen facing down. Never poke the holes with a pin or a tool.
Why seals wear out
Water resistance comes from gaskets, which are rubber-like rings compressed between the case, the back, the crown and the buttons. They are not permanent. Over time they lose their elasticity, harden, collect grit and tear. A few habits speed that up:Sudden temperature changes, such as moving from a hot room straight into cold water.
Opening the case, including a battery swap at a shop that does not replace the seals.
Knocks to the case or glass that shift the gasket out of position.
Chemicals left on the gasket, such as soap, sunscreen and chlorine.
Repeated use in conditions the manual excludes.
The rating printed on the box describes the watch when it was new. Check the seals after a drop, after every battery change, and regularly if you swim often. Watch for fogging or moisture under the glass, water that appears after a wash, or a watch that resets or misbehaves after water exposure. Stop using it in water and contact the maker or an authorised service centre.
Aftercare after water exposure
- Rinse the watch and strap under plain tap water after pool time, sea swims or heavy sweating.
- Dry the outside with a soft cloth and let the strap air dry away from heat.
- Look for moisture or condensation under the glass. If you see any, do not charge the watch.
- Charge only when the case and the charging contacts are completely dry.
- Do not blow hot air into the case or the speaker holes with a hairdryer.
Reading the manual
The manual has the final word. Look for the rating, the conditions it covers, and any notes about swimming, diving, hot water and cleaning. The table below sums up what each marking tells you and what it leaves out.| Marking | What it tells you | What it does not tell you |
|---|---|---|
| Dust and water code | Protection level in a defined test for dust and water | Whether swimming, diving or hot water is safe |
| Pressure-depth rating (ATM, metres or feet) | Static water pressure the case withstood in a laboratory | Whether the watch suits diving or moving water |
| Swimming note in the manual | The maker allows swimming use | Whether salt water, soap or heat is fine |
| X in place of a code character | That category was not tested | Anything about that category |