Understanding the Water Resistance of Your Watch

Understanding the water resistance of your watch is vital for ensuring its longevity and functionality. In this episode of The Classroom, Michael from WatchBox Studios takes you through the importance of regularly inspecting your timepiece and the best practices for keeping it safe from water damage. He discusses the various tests watches go through, such as vacuum and pressure testing, to ensure their integrity. Michael also shares a condensation test that you can perform at home to verify if your watch is water-resistant. By learning about these tests and taking proper precautions, you can enjoy swimming, diving, and other water activities without worrying about damaging your watch. Remember to have your watch checked every three to five years to maintain its optimal performance.

Understanding the Water Resistance of Your Watch

Types of Watch Water Resistance

Water resistance is an important feature to consider when purchasing a watch. It ensures that your watch remains protected from water damage, allowing you to wear it in various conditions without worry. There are different types of watch water resistance, each offering a different level of protection.

How water resistance is determined

The water resistance of a watch is determined by various factors, including the quality of the gaskets and seals, the construction of the case, and the type of crystal used. When a watch is manufactured, all the gaskets and seals are new and in perfect condition, ensuring that the watch is tested and rated for specific depths.

Different levels of water resistance

Watches are typically classified into different levels of water resistance, indicated by their water resistance rating in meters. The common ratings include:

  • Water Resistant (WR) or 30 meters (3 ATM): These watches can withstand splashes of water or brief immersions in water, such as washing your hands or getting caught in the rain.
  • 50 meters (5 ATM): These watches are suitable for swimming or showering.
  • 100 meters (10 ATM): These watches can be worn during snorkeling or swimming.
  • 200 meters (20 ATM): These watches are suitable for water sports such as scuba diving.

Testing Methods for Water Resistance

To ensure the water resistance of a watch, it needs to undergo various testing methods. These methods include non-destructive tests using vacuum and air, as well as testing under pressure.

Non-destructive methods using vacuum and air

A watch is tested in a vacuum because when you swim on your backstroke, as soon as you pass your shoulder, you are in a vacuum situation. There is a risk of water being sucked into the watch, which can cause moisture to condense inside over time. By testing the watch in a vacuum, it can be determined if there are any leaks that need to be addressed.

Testing in a vacuum

The watch is placed in a machine that creates a vacuum, causing the watch to expand in size. If there is a leak, the watch will relax to its natural state. The watch is then stabilized and monitored to ensure it remains expanded, indicating that it passes the first test.

Testing under pressure

After passing the vacuum test, the watch goes on to undergo testing under pressure. This involves compressing the watch together and then cutting off the air. The watch is observed to ensure it relaxes back to its natural state. Any problems with the seals are diagnosed during this process.

Diagnosing seal problems

All watches are tested for water resistance both when they come in for service and before they are returned to the customer. This ensures that all gaskets and seals are seated correctly and that the watch can withstand water exposure without any issues. Even with new gaskets, it is possible for a watch to fail water tests if even the smallest oversight is made.

Water Resistance Testing for Dive Watches

Dive watches undergo more rigorous water resistance testing due to their intended use in challenging underwater environments. These tests are conducted to 125 percent of the rated depth and time to ensure the highest level of water resistance.

Testing dive watches to 125 percent of rated depth and time

Dive watches are subjected to more extreme conditions than regular watches. They are tested to depths and times beyond their rated limits to ensure they can handle the additional pressure and exposure.

Forcing water into the watch

During the test, a dive watch is placed into an air chamber and compressed. This is done to simulate the conditions experienced during an actual dive. The watch is kept in the chamber for a significant amount of time, often longer than a typical dive, to ensure it remains water-resistant.

Condensation test

After the watch is removed from the air chamber, a condensation test is performed. This test can also be done at home. The watch is placed on a heated surface in direct sunlight for a period of time, and then an ice cube is placed on top of the crystal. If any condensation forms inside the crystal, it should disappear within one hour. If the condensation disappears, the watch is considered water-resistant with no moisture inside.

Testing for Moisture Inside the Watch

Moisture inside a watch can be detrimental to its functionality and lifespan. It is important to periodically test for moisture and take the necessary steps to prevent it from entering the watch.

Condensation test at home

As mentioned earlier, a condensation test can be done at home to check for any moisture inside the watch. By placing the watch on a heated surface and then applying an ice cube to the crystal, any condensation that forms can be observed. If the condensation disappears within one hour, the watch is considered water-resistant.

What to look for during the test

During the condensation test, it is important to observe whether any condensation forms inside the crystal and how long it takes to dissipate. If condensation persists or takes longer than one hour to disappear, it indicates that there may be moisture inside the watch, which requires professional attention.

Proper maintenance to avoid moisture

To avoid moisture entering the watch, it is important to properly maintain it. This includes ensuring that all gaskets and seals are in good condition, regularly checking for any signs of wear or damage, and having the watch professionally serviced every three to five years. By following these maintenance practices, you can minimize the risk of moisture-related issues.

Precautions to Take Around Water

While watches with water resistance are designed to withstand exposure to water, there are still precautions that should be taken to ensure the longevity of your timepiece.

Avoid winding or setting the watch when wet

When your watch is wet, it is not the ideal time to wind or set it. The moisture can compromise the gaskets and seals, increasing the risk of water entering the watch. It is best to allow the watch to dry fully before performing any winding or setting functions.

Avoid using the chronograph underwater

Using the chronograph function of your watch underwater is not recommended. When you push the chronograph buttons underwater, it can introduce water into the watch, leading to potential damage. It is advisable to use the chronograph function only when the watch is dry and away from water.

Recommended Maintenance Schedule

To ensure the continued water resistance and proper functioning of your watch, it is crucial to follow a recommended maintenance schedule.

Having your watch checked every three to five years

It is highly recommended to have your watch checked by a professional every three to five years. During this maintenance service, the gaskets and seals will be inspected and replaced if necessary, ensuring that the watch remains water-resistant. Additionally, other components of the watch will be examined and serviced as needed.

Importance of preventive maintenance and service

Regular maintenance and servicing play a vital role in the longevity and performance of your watch. By following a recommended maintenance schedule, you can identify and address any potential issues before they become more significant problems. This preventive approach helps preserve the water resistance and overall health of your watch.


Understanding the water resistance of your watch is important for ensuring its longevity and protecting it from water damage. Different types of watches offer different levels of water resistance, and it is essential to consider the specific water resistance rating when purchasing a watch. Regular maintenance, including testing for water resistance and observing proper precautions around water, can help prolong the lifespan of your watch. By following these guidelines, you can enjoy the functionality and reliability of your watch for years to come.