Water Resistance for Vintage Watches

What Water Resistance Really Means

Water resistance in watches refers to how well a timepiece can withstand pressure from water exposure, but it does not mean the watch is fully waterproof (nothing is waterproof). Numbers related to water resistance is usually measured in meters—such as 30 m, 50 m, 100 m, or 200 m— or bars (3 Bar=30 m). These ratings are based on static pressure tests in a lab, and indicate how much pressure the case and seals can resist under ideal conditions, not the literal depth you can dive to.

Common Water-Resistance Ratings Explained

• 30 m / 3 ATM is generally splash-resistant and safe for rain or hand washing, but not suitable for swimming or submersion.
• 50 m / 5 ATM may handle brief shallow swimming, yet it’s still not ideal for prolonged pool or ocean use.
• 100 m / 10 ATM is commonly considered safe for swimming and snorkeling.
• 200 m / 20 ATM or more is typically required for serious water activities and recreational diving. 

Why Vintage Watches Lose Water Resistance

Water resistance relies heavily on the condition of gaskets, seals, crowns, crystals, and case construction. Over time, these components degrade due to age, temperature changes, impacts, and wear. Repeated exposure to chlorinated or salt water can permanently damage metal gasket surfaces and cause corrosion at sealing points.

Even watches originally rated for high depths will lose water resistance if:

• Crowns or pushers are not properly sealed or screwed down
• Gaskets have hardened or deteriorated
• The watch has not been pressure tested or serviced regularly

Water resistance is not a permanent condition, especially in vintage watches.

Servicing Vintage Water-Resistant Watches

I regularly service vintage Rolex Oyster watches, vintage dive watches, and other timepieces originally designed with water-resistance certifications. Depending on the design and condition of the case, I often recommend caution around moisture, even for watches that once carried significant depth ratings. My goal is to restore these watches to reliable mechanical operation while achieving reasonable water resistance where possible—but never at the expense of originality or safety.

Final Guidance

Vintage watches should be worn and enjoyed—but with caution around water. If you have questions about your specific watch or its water resistance after service, I encourage you to contact me directly.

Are you looking for Repair or Service of your Vintage Watch?

If you would like to initiate the repair of your vintage timepiece contact me directly, or visit getting started.

For additional information on watches we work on please visit these pages:  Vintage Rolex repair— Vintage Breitling repair —Vintage Omega repair — Vintage Heuer repair —Bulova Repair, and Pocket Watch Repair. See my FAQ for additional information, and visit Watch Repair Case Studies.