In the last decade, energy and water become the most important commodities as the world is suffering from a critical shortage in water and energy. Researchers are working hard on renewable energy, and energy saving. In this paper, an experimental study of the usable energy for domestic hot water storage tank was performed. Different supply features and different flow rates have been considered. To save energy in the storage tank, the turbulent mixing must be eliminated. In this study a cover over the supply lines was imposed. It has been found that the cover for the side supply feature improves the temperature distributions in the tank. For the bottom supply feature investigations indicated important improvement in the total usable hot water. Approximately 17% saving in usable hot water was achieved by using a round curved cover on the bottom supply line. The achieved saving in energy and hot water will help in reducing the consumed energy in residential buildings and thus keep us in a better environment.