Water-resistance numbers are easy to misunderstand when buying a pre-owned watch. A case back might show a depth rating, but that marking describes how the watch was designed and tested when it met the manufacturer’s specification. It does not prove that an older or pre-owned watch is still safe to use in water today.
What does a water-resistance rating mean?
Watch water resistance is normally expressed in metres, bar or atmospheres. These figures come from controlled testing rather than a promise that a watch can simply be taken to the stated depth in every real-world situation.
For a buyer, the important distinction is between an original specification and the current condition of an individual watch.
Why can water resistance change over time?
A watch case relies on components such as seals and gaskets around openings including the case back and crown. Their condition can change with age, wear and previous work on the watch. A pre-owned watch can therefore look excellent and function correctly while its present water resistance remains unknown.
Does “100 m” mean a pre-owned watch is currently water resistant to 100 metres?
Not necessarily. If a listing describes a watch as “originally rated to 100 m,” that is different from saying the individual watch has recently passed a pressure test. Unless a current test is stated, buyers should not assume that an original depth rating has been preserved.
This distinction is especially useful when comparing watches in our current watch collection. SEKUND product descriptions aim to separate known specifications from the present condition of the individual watch.
What should you check before buying?
- Read the wording carefully. Look for whether the seller is describing the original manufacturer rating or a recent test.
- Check the condition description. Case, crown and other visible condition information can help you understand the watch, but appearance alone cannot confirm water resistance.
- Do not treat normal operation as proof. A watch keeping time correctly does not demonstrate that its seals are watertight.
- Ask about pressure testing if water use matters to you. A recent test is much more relevant than relying only on a historic specification.
What is a pressure test?
A watchmaker can test the case to assess whether it meets a specified level of water resistance at the time of testing. This is useful when you intend to expose a pre-owned watch to water. Testing does not make every watch suitable for every activity, so the intended use and the watchmaker’s advice still matter.
How should you treat an untested pre-owned watch?
The cautious approach is simple: if current water resistance has not been verified, avoid exposing the watch to water. This is particularly sensible for older watches where preserving the dial, movement and case matters more than testing the limits of an historic rating.
Water resistance is only one part of choosing a watch
Movement type, condition, size, crystal, dial and how you plan to wear the watch can all matter more than a depth number. If you are comparing different types of movements, read our guide to quartz, mechanical and automatic watches. For broader buying advice, see how to buy a pre-owned watch online safely.
You can also browse watches currently available from SEKUND. Availability changes as individual pre-owned watches are sold.