Hydration plays a particularly important role in health maintenance and general well-being. A wide assortment of drinking waters are currently available on the market. However, their ability to hydrate may vary. For studying hydration, a useful organism may be the cysts of brine shrimp. Those cysts may remain dehydrated and functionless for years, but regain function once hydrated. In this study, we first determined the optimal factors for assessing hydration in the brine-shrimp model, including aeration method and flow rate, salinity, and temperature. Various kinds of water, including tap water, bottled water, and water containing health-promoting agents, were tested by using this new method to evaluate their ability to hydrate. Tap water showed weak hydration, while some bottled waters (e.g., Kirkland Signature Purified Water) hydrated more effectively. Mineral water, such as Fiji water, was found to be a desirable option to maintain adequate and lasting hydration.Graphic abstract