Water scarcity is a serious global problem that mainly affects areas that are in arid and semi-arid climates. To overcome this issue, conventional desalination techniques have been used, but they frequently involve substantial energy inputs, have high operating costs and have an adverse effect on the environment. In recent years, solar desalination (SD) using solar still (SS) has emerged as a potential and sustainable alternative. In this study, a double slope solar still (DSSS) is employed to investigate the utilization of solar energy in the desalination process. The objective of this study is to analyze how the productivity of the DSSS is affected by variations in water depth (WD). The WD inside the basin varies between 5mm, 7.5mm and 10mm. A multi-phase 3D model of the SS is designed and created using Design Modeler which is a design module of Ansys Workbench. This is followed by CFD simulation in Ansys Fluent 2023 by using the atmospheric conditions of Shillong, Meghalaya, India (25.57°N, 91.89°E). With an increase in WD within the DSSS, there is a corresponding decrease in the temperature of the glass, water, and basin. This has an impact on the still's output since the amount of freshwater that can be generated is directly related to the difference in temperature between the glass and water. Thus, decrease in the water level of the still, increases the supply of freshwater.