The modder/watch tech named "Vaccum" on this forum will pressure test your watch to 10ATM for 40 bucks.
Great insurance.
Quality replicas of diver watches can be perfectly waterproof. Just dont blindly trust them to be so. every replica is a unique case. What if the guy who built your watch made 100 reps that day, and left a gasket out of 3 of those by accident. you get one of those three. Whoops.
Dont pay mind to the big ballers who say you can't snorkel with a rep. Hell, those guys say you can't even dive with a gen Submariner. No enough depth rating! Whatever