Given the increasing development of RENEWABLE energies and their worldwide growing significance, specifically in developing countries such as Iran, focusing on the ways of storing this kind of ENERGY, as the main issue in this area, is a priority. Since RENEWABLE ENERGY production is strongly dependent on the climate conditions, the full time reliance on them for providing power and other applications is not possible and therefore, for the moment, responding to the whole ENERGY demand, by solely depending on RENEWABLE ENERGY is not an option. Storing ENERGY contributes to keeping the balance between demanding and providing ENERGY, by immediate discharge of it in the time of need. Among various Storing solutions, water, due to its capability of converting potential ENERGY to kinetic ENERGY, has the capacity of storing and discharging vast amount of ENERGY to facing the demand. The present work, describes different methods and solutions of utilizing water as ENERGY storage. Some of these methods have been used for a long time, while some others are considered to be fairly novel with a long way ahead to become fully developed and commercialized.