No watch is fully impervious to water, leaving all watches on the market today "water-resistant". In fact, in the United States, it is illegal to officially declare any watch "waterproof." The term was abandoned several years ago because watches are only capable of resisting water to a certain extent; it is impossible to make a watch waterproof.

To construct a water-resistant watch, gaskets are used to create a tight seal among the major components. Since the gaskets are often created from rubber or silicon, they may break down over time. Many jewelers suggest having a water-resistant watch inspected for signs of damage every few years, in which case the seals are replaced. If the watch will be exposed to water, it is important to buy a piece intended for the right purpose. There is no way to modify a regular watch to become water-resistant.

Manufacturers use a scale of resistance to provide information about a watch's ability to resist water. Watches resistant to 50 meters are suitable for general swimming, while 100 meters is recommended for snorkeling, 200 meters is required for scuba diving, and 1,000 meters can tolerate deep-sea diving. It is crucial to remember that although water-resistant watches are tested thoroughly, many remain motionless during the testing process. To ensure that a water-resistant watch will withstand a combination of movement and pressure, it is wise to invest in a piece that meets more than the basic requirements of the individual.

Water-resistant watches are fairly easy to maintain. Unless specifically treated for regular exposure to water, leather straps are not a good choice. To preserve the value of the watch, it is best to select straps composed of materials such as plastic, rubber, vinyl or metal. Avoid contact with harsh chemicals, such as cleaners or excessive chlorine, which can erode the special seal. Rinse the watch thoroughly after swimming in salt water.

Heat is the most damaging element to water-resistant watches. Avoid wearing this type of watch in hot tubs, saunas, showers or baths because it can cause the components to expand at different rates, leaving gaps in the seal. Sudden temperature changes can also be harmful, for example, moving directly from a hot tub to a cold swimming pool.

When shopping for a water-resistant watch, remember that purpose, estimated amount of water exposure, and type of strap are just as important as price. Be sure to inspect water-resistant watches regularly for signs of damage or water penetration.