Are Automatic Watches Waterproof? Water Resistance Guide

A lot of watches, regardless of movement type, is marketed as “waterproof”. However, saying a watch is waterproof sounded a bit sketchy to me. Therefore, I started to do some research to understand the waterproofness of watches. Since I own multiple watches myself and want to avoid any water inside the watch, understanding waterproofness seems like a good idea.

No watch is waterproof. Watches should not be seen as waterproof, but rather water-resistant. The water-resistance of a watch is indicated in meters, ATM, or bar on the case or dial of the watch. Anything with a water resistance greater than 200 meters is seen as adequate for water activities.

I am assuming that since you googled whether automatic watches are waterproof, you either want to know something about the water resistance rating or whether your (next) automatic watch can handle water. I will guide you to better understand the water-resistance of your watch though this post.

Are Your Automatic Watch Waterproof?

Sadly, just because you have an automatic watch is doesn’t become waterproof. However, there is a decent chance that you have some kind of water resistance on the watch.

Most watches are equipped with some level of water resistance, and it can easily be found either on the dial of the watch or the backplate.

While it is a bit difficult to see, the image on the left has a water resistance indicator of 100 meters (10 ATM or BAR). The watch on the left has a water resistance of 300 meters (30 ATM or BAR).

Each watch has different purposes, the one of the left is a classic dress watch, and the other one (right picture) is a diving watch.

While water won’t kill an automatic watch, it will need an expensive repair if the movement gets flooded.

Whereas if a quartz movement gets water, it will permanently die. The water resistance required for your watch depends on your needs.

If you are a scuba diver on the weekends, having a 50 meters water resistant watch ain’t gonna cut it.

The need for water resistance in automatic watches are quite reasonable to understand. A full repair of a flooded watch can easily cost $800.

This is also one of the reasons you will see automatic dress watches with a water resistance of over 100 meters on leather straps.

The watchmakers simply know the importance of the water-resistance for the customers, even on watches that is not intended to have any contact with water.

On most watches, the first indicator of the water-resistance will be a meter measurement. However, you will encounter both BAR and ATM.

One bar is 100,000 pascal or 0,987 ATM. ATM is short for atmospheric pressure. There is approximately 1 ATM at sea level.

Each BAR or ATM is equivalent to ~10 meters of water resistance. For example, 5 ATM or BAR is equal to 50 meters. 12 ATM or BAR is equivalent to 120 meters. Easy right?

Since most automatic watches are costly for the average enthusiast, most watch owners wouldn’t want to pay for a full repair each time some rain hit the watch in addition to the regular maintenance costs of an automatic watch.

Guide To Water Resistance

Using a watch near water is perfectly fine if the watch is rated for whatever activity you are about to participate in.

For activities such as diving, screw-down crowns are highly recommended. A regular crown that is just pushed in does not tightly seal against the gasket. In comparison, a screw-down crown is gently forced onto the gasket to ensure a complete seal.

For divers of great depth, helium escape valves are recommended. Commercial divers working at down to 70 meters spend hours in diving bells helium gasses can move around.

Helium atoms are the smallest natural gas-particle and can enter the watch around the gaskets of the watch. While the diver is under pressure, the helium is not a problem.

However, when the diver starts ascending and decompression stops is not long enough, a pressure difference can build up between the helium gas and the surrounding environment.

The most common damage is the crystal of the watch popping off. For the average user of a dive watch, the helium escape valve is just a cool gimmick.

For watches with additional complications such as chronographs includes extra entries for the water to the movement of the watch. For each extra hole in the case of the watch, you add a place for the water to enter.

My watch specialist recommends:

• Get the watch pressure tested once per year.
• Avoid frequent use of chemicals on the watch.
• Avoid frequent cleanings of the watch with soaps or dissolvents.
• Ask your jeweler to apply oil to the gaskets (known as “O” rings) and replace the gaskets.
• Always make sure the crown(s) are screwed tight before going near the water.
• Never use the crown or pushers underwater, no matter what water resistance is indicated on the watch.

Water Resistance Chart	>30 meters 3 BAR	50 Meters 5 BAR	100 Meters 10 BAR	200 Meters 20 BAR	<300 Meters 30 BAR
Splashes/Washing hands/Rain	✓	✓	✓	✓	✓
Beach/Swimming pool	✕	✓	✓	✓	✓
Water activities (Jetski, water skiing, pool parties, etc.)	✕	✕	✓	✓	✓
Amateur diving	✕	✕	✕	✓	✓
Serious diving (Scuba diving)	✕	✕	✕	✓	✓

How Water Resistant Should Your Watch Be?

The water resistance needed for your watch depends on the need for the water-resistance itself. If you are a scuba diver, you would need at least 300 meters or more to be sure the watch will withstand the dynamic pressure of swimming. A certified divers’ watch is branded with DIVER’S WATCH x M, DIVER’s x M, or DIVER’s WATCH x M FOR MIXED-GAS DIVING, where “x” is the rated water depth.

There are two types of standards for the water-resistance of a watch: the ISO 22810 standard and the ISO 6425 standard. The ISO 22810 was introduced in 1990 and intended to be used on watches that should only be used with light water exposure. The ISO 6425 was introduced in 1996 and meant to test the true diving watches. In act, the watches tested/certified with ISO 6425 are tested at 125% of their rated pressure. Therefore, a 100 meter rated watch will be tested at 125 meters pressure.

The ISO 22810 goes through what is necessary for the average user of a watch, such as condensation and lower external pressure. The ISO 22810 goes through the following tests:

• Test for condensation: watch is heated to 40-45 °C (104-113 °F). A drop of water with the temperature of 18-25 °C (64-77 °F) is added to the glass. The watch is dried with a towel after 1 minute. If any condensation has appeared to the inner surface of the glass, the watch is disapproved.
• Submersion in water at 10 cm for 1 hour.
• Submersion in water at 10 cm with a force of 5 Newton perpendicular to the crown and other pushers for 10 minutes.
• Temperature change is tested with a regulation temperature with a sequence of 40 °C – 20 °C – 40 °C (104 °F – 68 °F – 104 °F). With any sign of water intrusion or condensation, the watch will be disapproved.

However, what is not tested in the ISO 22810 standard is magnetic or shock resistance, negative pressure, or corrosion.

When looking for your new watch that is only meant for daily wear (and not swimming, diving, or other water activities), the ISO 22810 tested watches will be just fine. However, if you are going to use it for a lot of diving, swimming, or similar activities, you should look for a watch with is rated for above 100 meters water resistance.

The ISO 6425 standard has a similar rulebook. However, it is more strict and designed for more extreme uses. The ISO 6425 standard is intended to test watches that can withstand at least 100 meters of depth, and ensure full reliability and accuracy during such depths. The ISO 6425 goes through at least the following:

• To test the reliability of the watch, it will be submerged to a depth of 30 cm for 50 hours at a temperature of 18-25 °C. All mechanisms must perform with no issues after the test.
• Test for condensation: watch is heated to 40-45 °C (104-113 °F). A drop of water with the temperature of 18-25 °C (64-77 °F) is added to the glass. The watch is dried with a towel after 1 minute. If any condensation has appeared to the inner surface of the glass, the watch is disapproved.
• The crown and pushers is tested to an external force. The watch will be overpressurized to 125% of its rated water resistance for 10 minutes.
• A water tightness and water overpressure is tested using the same method of 125% of it rated water resistance. The watch shall be applied to 125% of pressure within 1 minute and maintain the pressure for 2 hours. Subsequently, the pressure must be reduced to 0.3 ATM within 1 minute and maintain 0.3 ATM for 1 hour. The watch shall show no sign of water intrusion or condensation.
• Temperature change is tested with a regulation temperature with a sequence of 40 °C – 5 °C – 40 °C (104 °F – 41 °F – 104 °F). The transition time between temperature changes shall not exceed 1 minute. With any sign of water intrusion or condensation, the watch will be disapproved.

There are additional tests in the ISO 6425 standard. However, it does not concern the water resistance. A certified ISO 6425 watch will be branded “DIVER’S WATCH x M” or “DIVER’S x M”, where “x” is the rated water depth.

How Is The Water Resistance Tested?

A watch’s water resistance is tested in a controlled environment. The water-resistance of a watch is all about pressure and technically not the water depth. The pressure test done in compression chambers under a static pressure. While the static pressure might measure a water resistance of 200 meters, having a garden hose spray at full power is a dynamic pressure which might not equate to 200 meters or 20 bar of static pressure.

See the way it works is that when a watch is getting tested in a pressure chamber, it is laying dead-still – no movement at all. When the watch is submerged in the pressure chamber, the pressure is added to verify its rating. If the watch were to be moved while it was pressurized, there would be additional pressure added to the watch in the direction of the movement. Therefore, swimming with the watch at a depth of 50 meters, does not equate to 5 BAR/ATM but more than the 5 BAR/ATM.

Wet testing: The watch is placed in the pressure chamber with water. The watch starts above the waterline, where the pressure is applied. When the adequate pressure is reached, the watch is submerged in the water. The pressure will gradually be released from the pressure chamber. If the watch is not water-resistant, air will leak from the watch (shown by bubbles).

Dry testing: Dry testing works by pressurizing the chamber with the watch inside. The watch has a gauge sat on the crystal to measure case or crystal deformation.