Everything you need to know about water resistance

Before you start dive bombing in the pool, read this to find out if your watch is really waterproof. You have your brand-new watch in your hands, admiring it. You strap it on and it feels great. Then, the next day you jump into the pool, forgetting that the watch is on your wrist. Is it ruined? It is water proof? Well, here’s the truth about water resistance, to help ease your mind.

First off, if you have a watch that is at least 50 meters water resistant, you should be fine for showering, washing your hands, jumping into the pool and more. There are dedicated dive watches that are water resistant to 200, 300, even 1,000 meters (the world record is 6,000 meters/20,000 feet, held by CX Swiss Military Watch), but for casual, non-SCUBA diving use, you should be fine with 50- or 100-meter water resistance.

Water Resistance History

In the beginning, watches were not water resistant at all. The cases were closed, but water could still get in. Then, Rolex introduced its Oyster case in 1926, which allowed watches to go into the water without suffering damage.

Many companies followed suit and today most watches have a water resistance rating – the specs tell you how far down the watch can go without being compromised. Most watches are sealed with a gasket that blocks water, dust, air and more from getting into the watch. This gasket’s size, thickness and the case design determine how far down the watch can go before water gets in.

Under Pressure

Even though we use meters or feet in water resistance, BAR is a better designation, as it is represents the pressure when the watch goes underwater. The deeper you go, the more pressure is exerted against the watch case. The watches with higher water resistance build in special gaskets, automatic helium release valves to dispel the gasses that build up, and more. Luckily, one BAR is equal to 10 meters, so when a watch is listed at 100 meters water resistance, that is 10 BAR.

How low can you go?

The depth ratings you see on watches can be deceiving, as 30 meters/three BAR of water resistance doesn’t necessarily mean you can dive down to 30 meters without any problem. Watches are water tested in a laboratory, with the watch sitting absolutely still as air pressure is increased to simulate water pressure. It has become more popular recently for high water resistance watches to be tested in actual water, but for most watches, they are still tested using air pressure.

What about showering?

And, we have to remember that water pressure is not static. Standing under the shower with the water hitting your watch can generate significant water pressure, up to 30 meters/three BAR or more, and if you go swimming the movement of the watch can increase the pressure as well. In fact, the most critical time for a watch is when it is first submerged in the water, because the gaskets that protect the watch haven’t yet had a chance to seal — the pressure helps to push the gaskets and maintain the water resistance. This is why it’s important to have your watch serviced regularly, so the gaskets can be changed out if they are worn or brittle.

Advice for water lovers

If you aren’t planning to shower with your watch on and won’t go swimming with it on, you should be fine with 30 meters and up. If you know you will be swimming, hot tubbing, paddle boarding and more with your watch on, make sure the timepiece you choose is water resistant to at least 100 meters and preferably more. If you are going to SCUBA dive with your watch on, you need a proper SCUBA Dive watch, which has several key requirements: at least 200 meters water resistance, a uni-directional bezel, great legibility underwater, a running seconds indicator and more.

The higher the better

All of us like to have a watch that we don’t have to worry about, and the higher the level of water resistance your watch has, the better. Dive watches, for example, are heavily tested and have to confirm to ISO standard 6425 (which includes shock resistance, temperature resistance and more), so they are tougher and more durable than ordinary watches.

So, if you are going to be hard on your watch at all, think about getting a watch that has at least 100 meters of water resistance. You will be thankful you did, even if you don’t drop it into the pool.