When you read ads for watches you see specifications such as ”water resist 10m” and you wonder what that actually means and how it compares to ”water proof 30 ft.” or similar.
First of all watches and water do not mix very well. Unless your watch is actually a scuba watch, do not go scuba diving with it. Even if it says that it is ”water resistant 50 m” it does not mean that you can take it down 20 m below when you go wreck-diving. In fact this watch should not be taken to a swim at all and the 50 m can be quite misleading.
Water resistant means the water have some resistance to water but it does not mean it is intended for you to go swimming with it. In fact you should never submerge a watch marked only ”resistant” and if you are out in rainy weather where there is enough rain to soak your sleve or rain directly on your watch do not press any buttons or wind it before it has dried up properly. Doing so may allow water to get inside the watch and cause all sorts of future problems (foggy glass being one indication that this has happened).
In the beginning watches were classified as either ”water resist” or ”water proof” sometimes the latter followed by a number, 10m 50m 100m being the most common.
Water resistant
A water resistant watch is never intented for swimming or to be sumerged. If the water resist mark is followed by a number you can interpret this as the maximum number of minutes the watch should in any circumstance be exposed directly to light rain!
A water resistant watch can be washed gently with water if it needs to be, but avoid running tapwater and avoid detergents at any cost! Detergents such as washing-up liquid or similar causes the natural water tension to break down and allows the water to penetrate through buttons, windup axis or similar, even through a rubber seal!
Instead use a soft moist cloth and rub until shiny again. Alcohol solvents can sometimes be used, but the watch band might not like it and it can dry out the rubber seals in the watch.
Water proof
The way the seal on the watch is tested is that it is submerged in a chamber partly filled with water. Then the air pressure is slowly increased until such time that the pressure corresponds to a certain depth, usually measured in meters (1 meter about 3 ft.) and as long as there are no bubbles the test is deemed successful.
There are a number of reasons why this test is misleading, when you are swimming you are forcefully moving your watch through the water creating turbulence and various pressure, the test described above is for a watch at perfect rest in still water. For the same reason you should avoid washing your watch under a running faucet since this will also increase the risk for water to get into the watch.
That bubbles are not coming out of the watch does not for certain show that water did not go into the watch! Air compresses under pressure and therefore it is possible for water sometimes to penetrate the watch seals without there being any air bubbles.
To make things more confusing, new watch makers sometimes themselves confuses the water resist and water proof marks making it quite hard for the consumer to know what is right. Therefore I have here a table based on personal experience with wrist watches and people I have talked with in the business of repairing said clocks:
Table of watch water resistance
[table=7]
Avoid showers
Showering with a watch is a terrible idea, even if the watch is water proof enough to withstand the sprays from the shower, the soap and other things used to wash yourself will have some effect on the water tension allowing it to transgress even good rubber seals and get in to the watch. It may also leave residues on the watch itself or affect the wristband. Never wash a leather strap with water, use ”saddle soap” or similar products intended to gently clean leather.
Always dry the watch gently after it has gotten wet and let it sit for a while to dry out. Place it somewhere where the temperature is slightly above room temperature but not to any extremes and leave it there for a few days.
Swimming with a watch
When you are swimming with a watch that is okay for this but not considered a scuba watch never press any buttons or use the wind-screw or operate the watch in any way unless it specifically says in the manual it isd intended to work that way and you are covered by warranty should the watch break.
Many outdoor watches sometimes have a ”snorkling mode” where the air pressure barometer inside used to calculate the altitude can be used to show how far under water you are. Avoid this function, it may look fun but if the water is not classed to be a swimming watch do not take it swimming. As simple as that.
A training watch with heart rate monitor can sometimes be used swimming, but the same thing goes, set the watch up before you go into the pool and then avoid pressing its buttons while in the water! Most heart rate monitor bands that you strap across your chest and communicates with the watch will not work while in water anyway (and they might not be water proofed either). Suunto has a collection of such watches with a ”memory” inside the chest strap that remembers your heart beat that will be transferred to the watch when you get out of the water again. Check the manual and ask the sales rep what is okay.
Sweat
Sweat generally do not affect watches that bad. Sweat is salty and moist and that should be a lethal combination for most electronics but it usually does not penetrate into the watch. However, after exercising with a watch there might be a good idea to give it a nice wipe-down or if the watch can take it, rinse in water. When you rinse a watch never run it under the fauced. Instead make a small ”bath” for the watch, lower it into the water for a few seconds then take it up again and dry with a soft cloth. Leave to dry over night before you use it.
If the accident happens
If you happen to get water into the watch you need to consider if it is a fully mechanical operation (wind-up or auto-winding watch) or if it is an electro-mechanical or fully electronic watch. With the later two it is important to immediately open the watch and remove the battery to avoid damaging the electronic circuits. If you have moisture inside the watch and the battery stays connected it will causes various salts and other pollutions in the water to deposit and eat away at the delicate circuitry. If your watch is a fully mechanical one take it to a repair shop and ask them to oil it up and check the water proof seal to replace if necessary.