Water resistance is the most misunderstood specification on a watch, partly because the units invite the wrong conclusion. Five bar is not “safe to fifty metres”. It is a static pressure test in a tank, and it says nothing about a dive into a pool.

What the bars mean

One bar is roughly the pressure of ten metres of water, static. A watch rated 5 bar survived a static test at that pressure — with the crown screwed down and the case undisturbed. A hand entering water at speed creates a momentary spike far above the static figure.

The parts that decide it

Water resistance is not the case metal. It is three gaskets and one thread: the caseback gasket, the crystal gasket, the crown gasket, and the crown tube thread. Any one of them being dry, dirty or worn ends the rating regardless of what the dial says.

Heat is the enemy

A hot shower or a sauna cycles the case between temperatures, expanding and contracting the gaskets. That is what kills water resistance over years — not swimming. A watch rated 10 bar can lose its rating in three summers of daily saunas without ever being submerged to depth.

What we do before dispatch

Every watch is pressure tested to 5 bar after casing, with new gaskets fitted as standard, and the result is recorded. For references rated higher, the test is run to the rating. If a case fails, it is rebuilt rather than shipped with a note.

If you have a watch that fogs after a shower, the gaskets are done. We replace and re-test as a same-week service.