sampling procedures concerning procedures regarding lot sampling testing come into play, since not every single watch has to be tested for ISO 2281 approval.

ISO 2281 water resistance testing of a watch consists of:
* Resistance when immersed in water at a depth of 10 cm. Immersion of the watch in 10 cm of water for 1 hour.
* Resistance of operative parts. Immersion of the watch in 10 cm of water with a force of 5 N perpendicular to the crown and pusher buttons (if any) for 10 minutes.
* Condensation