Water Resistance Explained: What ATM Actually Means for Your Watch

If you've shopped for a watch, you've probably seen ratings like "5ATM," "10ATM," or "20ATM" and wondered what they actually mean for how you can wear it. It sounds technical, but it comes down to one simple question: how much water pressure can your watch handle before it lets water in?

Here's what each rating really means — and what it doesn't.

What Does ATM Mean?

ATM stands for "atmosphere," a unit of pressure. One ATM is roughly the pressure at sea level. A watch rated 5ATM can handle pressure equivalent to being 50 meters underwater — but that number is tested in controlled, still-water conditions, not real life. Movement, temperature changes, and water pressure from splashing or diving all add extra strain that the rating doesn't fully account for.

That's why the safe, practical read on each rating is more conservative than the math suggests.

5ATM (165 ft)

Safe for: washing your hands, getting caught in the rain, light splashes.

Not safe for: swimming, showering, or any submersion. At this rating, treat your watch as splash-resistant, not swim-ready.

Looking for a 5ATM watch? R2 and Regent are both great picks in this range.

10ATM (330 ft)

Safe for: swimming, showering, and everyday water exposure.

Not safe for: high-impact water sports like diving or water skiing, where sudden pressure changes are harder on the seals.

Watches like Volunteer, Vigore, and Apex Run all carry a 10ATM rating — solid everyday choices if you swim occasionally or just want extra peace of mind.

20ATM (660 ft)

Safe for: swimming, snorkeling, and most recreational water activities without a second thought.

Not safe for: professional scuba diving, which typically calls for a dedicated dive watch with a specific ISO diving certification — a higher bar than a standard water-resistance rating alone.

Our Space City, TXN42, and Oceanaut are all rated 20ATM — built for real water use, not just the name.

A Few Things That Void Water Resistance Faster Than You'd Think

Adjusting the crown or pushers underwater — even on a highly water-resistant watch, this can let water in.

Hot showers — heat causes gaskets to expand and contract, weakening the seal over time.

Age — water resistance isn't permanent. Gaskets wear down, so a watch that was rated 10ATM new may not perform the same after a few years without maintenance.

Finding the Right Rating for How You Actually Live

If you're mostly wearing your watch day-to-day with the occasional splash or hand-wash, 5ATM covers you. If you swim regularly or want one less thing to think about in the shower, look for 10ATM or higher. And if water is a serious part of your routine — swimming laps, snorkeling, spending real time in the water — 20ATM gives you the most breathing room.

Every watch in the Logic Watches lineup lists its exact water resistance rating on the product page, so you can match the watch to how you'll actually wear it — not just how it looks in a photo.

New to automatic watches too? See how automatic and quartz compare before you decide what's right for you.