UNDERSTANDING WATER RESISTANCE: WHAT THE NUMBERS REALLY MEAN - EP 4

UNDERSTANDING WATER RESISTANCE: WHAT THE NUMBERS REALLY MEAN - EP 4

When choosing a watch, one of the most misunderstood features is water resistance. You’ve probably seen terms like “30m water-resistant” or “10 ATM” but what do those numbers really mean? Contrary to what many believe, they don’t always refer to how deep a watch can go underwater. Instead, they indicate how well a watch can withstand exposure to water under specific conditions.

At Montare, every detail from dial design to case construction is considered carefully. Understanding water resistance helps you appreciate how your watch is built and how to care.

 

WHAT DOES “WATER RESISTANCE” ACTUALLY MEAN?

Water resistance refers to how well a watch is protected against water ingress. It’s not a guarantee that a watch can be used for diving or swimming at the depth stated. Rather, it’s a standardized measure tested under laboratory conditions usually at a static pressure, without movement or temperature changes.

In the real world, factors like motion, temperature fluctuations, and ageing seals can significantly affect performance.

 

 

THE RATINGS EXPLAINED

30 Metres / 3 ATM / 3 Bar

  • Meaning: Splash resistant only.
  • Suitable for: Everyday wear, rain, or light hand washing.
  • Not suitable for: Swimming, showering, or submersion.
  • Reality: The watch can handle light moisture but not sustained exposure to water.

50 Metres / 5 ATM / 5 Bar

  • Meaning: Resistant to brief immersion in water.
  • Suitable for: Short swims in shallow water.
  • Not suitable for: Diving, snorkelling, or prolonged submersion.
  • Reality: A practical middle ground for everyday watches that might encounter water occasionally.

100 Metres / 10 ATM / 10 Bar

  • Meaning: Suitable for swimming and snorkelling.
  • Suitable for: Poolside activities, recreational swimming, and water sports.
  • Not suitable for: Deep-sea diving.
  • Reality: This level of protection is perfect for active lifestyles, and it can handle most daily water exposure confidently.

200 Metres / 20 ATM / 20 Bar

  • Meaning: Suitable for professional marine activities, surface water sports, and skin diving.
  • Reality: This is the standard for true dive watches. At Montare, we’re inspired by the craftsmanship of tool watches like these and built for function but admired for form.

300 Metres and Beyond

  • Meaning: Designed for professional diving environments.
  • Reality: These watches include advanced features such as helium escape valves and reinforced gaskets. While most wearers will never test their full capability, it’s a statement of engineering precision.

 

WHAT AFFECTS WATER RESISTANCE OVER TIME?

Even if a watch starts life with a 100m or 200m rating, its resistance can decline over time. Factors that affect performance include:

  • Gasket Wear: Rubber seals dry out and lose flexibility.
  • Shock or Impact: A knock can compromise case integrity.
  • Temperature Changes: Heat can cause seals to expand and contract, allowing moisture to enter.
  • Incorrect Crown Position: Leaving the crown unscrewed, even slightly, can let water in instantly.

To maintain performance, it’s recommended to have your watch’s water resistance tested and seals replaced every 1–2 years, especially if it’s regularly exposed to water.


ATM, BAR & METRES – WHAT’S THE DIFFERENCE? 

These terms are interchangeable ways of expressing pressure:

Measurement

Equivalent Pressure

Approx. Depth

1 ATM

1 Bar

10 Metres

3 ATM

3 Bar

30 Metres

5 ATM

5 Bar

50 Metres

10 ATM

10 Bar

100 Metres

However, it’s important to remember that these “depths” are based on static pressure. Real-world conditions, such as the force of a dive or movement of your wrist, can multiply that pressure meaning a 30m watch can easily be compromised under a running tap or swim stroke.

 

HOW TO CARE FOR A WATER-RESISTANT WATCH

  1. Always ensure the crown is fully pushed in or screwed down before exposure to water.
  2. Avoid pressing buttons or adjusting the crown while submerged.
  3. Rinse the watch with fresh water after swimming in salt or chlorinated water.
  4. Service regularly to maintain gasket integrity.
  5. Avoid extreme temperature changes like hot showers or saunas which can damage seals.


IN SUMMARY

Water resistance isn’t just about depth it’s about design, precision, and protection. From case gaskets to crown construction, every detail plays a part in ensuring reliability.

At Montare, we focus on creating watches that combine crafted durability with timeless design, ensuring they perform as beautifully as they look. Whether you’re caught in the rain or taking a dip on a summer afternoon, knowing your watch’s limits helps you wear it with confidence and care.

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