Water resistance
According to current standards, a wristwatch may be marked "water resistant" if it is able to withstand perspiration, water splashes or rain. It is not suitable for swimming.
If a watch is to be submerged in water it must be marked 5 BAR (50 meters) or more.

What makes a watch water resistant?
The parts that make a watch water resistant are gaskets or O-rings, made of rubber, Nylon or Teflon. The gaskets form a watertight seal at the joints where the glass, case back and crown meet the watchcase. Another factor to consider is the strength of the case, which must be able to withstand pressure without distorting.

How do I keep my watch water resistant?
Do not operate the crown or push buttons when the watch is wet.
After your watch has been in salt water or water containing chemicals, be sure to rinse it carefully in fresh water to remove any trace of salt and chemicals.
Your watch should not be worn in hot water.
Avoid chemicals (chlorine, perfumes, alcohol, hair sprays etc.)
All water resistant watches should have their water resistance checked every time the case is opened, for whatever reason.

MARKING	RECOMMENDED USAGE
WATER RESISTANT	Suitable for everyday use Splash/rain resistant NOT suitable for swimming
5 BAR 50 METRES	Suitable for water related work, recreational swimming & fishing NOT suitable for diving
10/15 BAR 100/150 METRES	Suitable for recreational surfing snorkelling, sailing & water sports NOT suitable for diving
20 BAR 200 METRES	Suitable for professional marine activity & serious surface water sports NOT suitable for diving

The above chart is part of a guide that has been developed by Jewellers and Watchmakers of New Zealand (Inc.) in conjunction with the major watch importers and wholesalers in New Zealand.

Please Note:
A new water-resistant watch will no doubt perform as is stated on its dial or back. However, there is no guarantee from the manufacturers or Peter Thomsen that the seals, gaskets or any other part of a watch will perform as new indefinitely.

Water-resistance is not a permanent condition
The seals, gasket, crown and glass are constantly under a lot of pressure and deteriorate with age and the elements.
If having a water-resistant watch is an important feature for you, I recommend that the watch be regularly serviced and tested.
I recommend that you have a watch exclusively for swimming and other watches for other occasions.

I CANNOT GUARANTEE THAT THE WATCH WILL NEVER LEAK.