There will be
link a number on the caseback
link or dial of your watch that lets you know relative water resistance but it's not as simple as
link "x number means I can do y thing in the water." It's a nuanced topic. It's wise to factor for the intent of the watch. A dress watch with 30 meters was likely never meant to get wet, while a 100m sports watch with a screw down crown could likely be used while diving.