How to Read Watch Water Resistance Ratings — A Complete Guide
Watch water resistance is marked on the caseback or dial using ATM, BAR, or M (metres). 30M / 3 ATM suits daily splashes; 100M / 10 ATM is swim-safe; 200M / 20 ATM is required for diving. Ratings are measured in static lab conditions — real-world movement increases water pressure significantly.
Step 1: Where to Find the Water Resistance Marking
Before buying or wearing a watch near water, locate the water resistance marking. Most watches engrave this on the caseback; some also print it near the 6 o’clock position on the dial.
If there is no marking at all, the watch has no water resistance and should be kept completely dry — including sweat and rain.
Step 2: What’s the Difference Between ATM, BAR, and M?
These three units measure the same thing — static water pressure resistance. Knowing the conversion lets you compare specs across brands instantly.
| Unit | Full Name | Conversion |
|---|---|---|
| ATM | Atmospheres | 1 ATM = 1 BAR ≈ 10 M |
| BAR | Bar (pressure) | 1 BAR = 1 ATM ≈ 10 M |
| M | Metres | 10 M = 1 ATM = 1 BAR |
Water Resistance Level Guide — MAVEN Model Reference
The table below maps each water resistance level to real-world activities and the corresponding MAVEN models. As a rule, choose a rating one level above your intended use for a comfortable safety margin.
| Water Resistance | ATM | Suitable for | Not suitable for | MAVEN Collection |
|---|---|---|---|---|
| 30M | 3 ATM | Splash resistance, handwashing, light rain | Swimming, showering, prolonged water exposure | MUS Quartz · THE DECO · THE ARTISAN |
| 100M | 10 ATM | Swimming, snorkelling, water sports | Deep diving | MUS Solar Chrono |
| 200M | 20 ATM | Diving, high-impact water sports | Saturation diving | MUS+ Automatic |
5 Essential Facts About Watch Water Resistance
The rating number is not your safe diving depth
A 30M rating does not mean you can use the watch 30 metres underwater. The rating reflects static lab pressure — movement multiplies real-world water pressure significantly.
Heat and steam are the enemy of water resistance
Heat degrades rubber seals through thermal expansion and contraction. Avoid hot showers, saunas, and hot springs regardless of the watch’s water resistance rating.
Never operate the crown or pushers underwater
Pressing any button or pulling the crown while submerged breaks the seal and lets water enter the movement — damage that is often irreparable.
Always reseal properly after a battery change
When replacing the battery, the caseback must be fully resealed. For screw-back cases, tighten every screw evenly in sequence to ensure the gasket compresses uniformly. It is recommended to have the battery replaced by a professional watchmaker to avoid compromising the water resistance seal.
Leather straps are not water-resistant — swap before swimming
Even if the case is water-resistant, a leather strap will degrade, stiffen, and smell when wet. Switch to a rubber or silicone strap before any water activity.
Frequently Asked Questions
Any watch rated 30M / 3 ATM or above can handle handwashing safely. Use cool water, and dry the case gap afterward. Watches with no water resistance marking should be removed before washing hands.
Yes. 100M / 10 ATM is suitable for pool and open-water swimming, and light snorkelling. It is not rated for scuba diving due to the increased pressure and temperature changes at depth. The MAVEN MUS Solar Chrono falls in this category.
Stop pressing any buttons immediately to prevent further water ingress. Place the watch face-up and away from heat sources. Bring it to an authorised service centre as soon as possible for inspection and drying.
The MAVEN MUS+ Automatic is rated 200M / 20 ATM, making it suitable for scuba diving and high-impact water sports. Other models — MUS Quartz, THE DECO, THE ARTISAN — are 30M splash-resistant; the MUS Solar Chrono is 100M swim-ready.
Find Your MAVEN Watches
From everyday wear to aquatic adventure — there’s a MAVEN for every level.
⌚ Explore all collections →
