Using your watch in water.

Many watches are able to be used in water but do we understand what type of water we can use our watches in? Then to add to the confusion, some watches are referred to being waterproof whilst some say water resistant, what is the difference? Well waterproof means that it is 100% sealed and water cannot get in to the mechanism in anyway; whereas water resistant means that the watch is able to resist the penetration of water to some degree. Many watches now have ATM engraved on the back and this refers to the pressure a watch can withstand, it may seem a little strange but ATM stands for atmosphere. 1 atmosphere is the normal atmospheric pressure a watch would be under when static at sea level and the pressure goes up (as does the rating) depending how much pressure the watch can be put under before it may break.

Generally watch manufacturers now use the term Water Resistant as no watch is totally waterproof and there is always a limit to how much pressure a watch can stand before letting water in, rather than the depth it can be used down to. For example if a watch was static in water with pressures of up to 30m (3ATM) then it could be down to that depth but when you start swimming that pressure increases. That means that a watch rated to 30m (3ATM) is only appropriate to be used in small amounts of water and is considered splash proof.

 30m (3ATM) – Splash proof and only used in small amounts of water

50m (5ATM) – Suitable for shallow swimming and can be submerged in water.

100m (10ATM) - Suitable for swimming, snorkelling and water sports.

200m (20ATM) – Suitable for novice Scuba Diving.

300m (30ATM) – Suitable for Professional and Deep Sea Diving.

 Some watches may have ‘ISO 6425’ or ‘Divers’ on it with a number written somewhere on the case or dial. This would usually signify that your watch can be used for diving or taking in the sea.

 Your watch maybe rated to swimming at the above pressures, however over time the water resistance may decrease due to shock or wear and tear. For example wearing your watch in chlorinated or salt water can speed up the time it takes for the watch to degrade. As can wearing your watch in a sauna or hot shower as heat can make the case expand and allow water inside it. To ensure your watch is up to a high standard we would recommend getting your watch pressure tested regularly.

Author: J Edwards