From a watchmaker point of view, I will mention from the beginning that the 2 don’t usually mix. This topic is very controversial but with over 62 years of combined experience and tens of thousands of watches worked on we have somewhat of a “say so” in this subject. However, if you need or desire to use a watch under water we recommend that you buy one that is inexpensive and can be easily replaced. For professional use buy one that is properly crafted to go under water.
A couple different meanings:
Waterproof – The watch is usable underwater, and water will not enter the watch when it is submerged
Water Resistant – The watch can withstand water being splashed on it and water will not enter the watch (such as from rain drops)
A proper watch that can go underwater:
- Must have a pressure fitted crystal (mineral glass, sapphire or acrylic)
- Must have screw in crown
- Must have screw in back
- Must have good gaskets
Secrets most manufacturers & most watchmakers don’t disclose or simply don’t know:
- Most watches are advertised as “waterproof” but it does not mean you can go swimming or shower with. It simply means that if the watch is accidentally submerged under water for a specific amount of time (usually will be only around 1 – 3 minutes at the most) water will not enter the watch
- Most watches are rated much higher than the pressure they can withstand (example: We won’t mention the name but a 200M Professional diving watch was tested at 20M by us and the bezel popped off the crystal shattered, and the hands bent). The watch was all original and not very old. Per clients request we did the pressure test
- Every time you change the battery you do not have to do a pressure test. It’s a way to make money off you. Of course, for peace of mind you can request a pressure test. Most watches are opened through the back to have the battery changed. If the gasket is bad the watchmaker can easily put a new one in (we do that included in the battery change for $5 if needed). If the gasket is not bad the watch will still be waterproof provided that the watchmaker closes the back properly. If a watch was waterproof it will still be waterproof after battery change. If a watch was not waterproof it will not be waterproof after battery change.
Misconceptions about watches to be used in water:
- Because most watches have a rating of 50M – 250M people assume that it can go under water and to the specified depth. Not true, even very inexpensive & fake watches will at least say 50M on the case back
- If a watch is waterproof people assume it is fine to shower with it. Not true, heat from the water will adversely affect the mechanism inside
- If a watch is waterproof people assume water will not affect it. Not true, in most situation if a watch is used in chlorinated water or salt water, it will slowly be affected from the outside. Even clean water over time will cause a watch to corrode from the outside and will find its way in places where it doesn’t easily dry and will begin to rust and corrode
Some things to consider (we’ve seen this on watches we’ve worked on):
- Any watch no matter how waterproof it was if it was ever used under water almost 99% of the time when we inspect inside there is evidence of some form of rust or corrosion, especially on the interior of the case edge
- Any watch no matter how waterproof it is when new it will over time deteriorate and will not be the same. So even if it was once waterproof it will not be so forever
- If you’ve used a watch under water for many years and water has not entered, it does not mean it was made to be waterproof, you may just be one of the “lucky” ones. Do not be surprised when water gets in
Some advice:
- Keep all vintage watches out of water regardless
- Keep any watch out of water in general to prolong its life
- If you must use a watch in water use a paper towel to dry it when you take it out, never use hot air from a blow dryer, and never put it in rice like cell phones (the microscopic debris is not good for the watch)
- Cans of air (duster) as used on electronics are great for removing water from under bezels and between bracelet links (so water will not rust the metal)
- When in doubt keep out of water
