Evaporation from open water bodies represents a major challenge to water conservation, particularly in arid and semi- arid regions where scarcity is intensified by high atmospheric demand. Conventional estimates indicate that 20–50% of stored water in reservoirs can be lost annually through evaporation, underscoring the need for practical suppression methods. This experimental study investigates and compares two approaches, monomolecular layers of cetyl alcohol and floating roofs using polyethylene balls, for their effectiveness in reducing evaporation losses. Laboratory-scale containers equipped with piezometers were used to monitor daily evaporation depths under three conditions: plain water surface, surface treated with a cetyl alcohol film, and surface covered with floating plastic balls. Results show that untreated water surfaces experienced an average evaporation loss of 15.57% of the storage volume, whereas the application of monomolecular films reduced the loss to 6.50%, and floating ball covers to 9.62%. Both methods proved effective and economical, with chemical films showing greater suppression potential and floating covers offering operational simplicity and reusability. The study demonstrates that integrating such methods in field-scale storages can significantly improve water-use efficiency, making them valuable tools for sustainable water resource management in evaporation-prone regions. This dual approach, combining laboratory validation with satellite-based evapotranspiration (ET) data using Google Earth Engine (GEE), provides a scalable framework for regional water conservation planning and enhances the reliability of findings for large-scale water management and policy adaptation.