Watch water resistance

People are often confused by what the stated water resistance of watches actually means.   Does a watch with “50 metres” as the water resistance mean you can dive with it as deep as 50 metres? No, you cannot.  So why do they write 50 metres on it?  Because it is referring to static pressure, not the actual depth of water it can be used in.  This is a common misconception.

50 metres refers to the pressure experienced if it was static at a depth of 50 metres.  When the watch moves the pressure rises well above a static pressure of 50 metres.  50 metres of static water pressure is easily achieved even in shallow depths.  Consequently, a 50 metres watch should not be used for diving, however it can be immersed in water.

Here are some common explanations of common water resistance standards:

Water resistant means splash proof.  Can withstand slight splashes, but NOT to be immersed in water.

30 metres / 3 ATM – splash proof and waterproof in small amounts of water

50 metres / 5 ATM – can be submerged in water

100 metres / 10 ATM – suitable for swimming and shallow diving

200 metres / 20 ATM – suitable for diving – not deep sea.

A new standard from Rotary is Dolphin.  Nearly all Rotary watches now have the Dolphin standard.  This means they are ‘waterproof’ and can be used in all water activities except deep sea diving.  This is a revolutionary concept from Rotary and means you can wear your dress water with the confidence that water will not enter the watch.

If you have the battery in your watch changed, you should be sure to have it resealed and pressure tested by the jeweller to ensure that it is still water resistant to the stated depth.