The world's need for potable water is continuously growing because of the industrial population and agricultural growth. Solar still is an available device that can be used for desalination of brackish and saltwater for drinking purposes. In this work, we study the investigation of the influence of the change of depth of saline water inside the basin of single slope solar still under the weather condition of south valley university, faculty of engineering, Qena, Egypt (Latitude:26.15878°, Longitude:32.71081°). And tested at real day time 8 A.M to 6 P.M on different five days from 20/8/2019 to24/8/2019, for different five water depths (0.5,1,2,3, and 5cm), and used vertical flax porous media to enhance the performance of solar still. Results showed that the freshwater productivity at depth of water 0.5cm higher than other depths (1,2,3,5cm). In addition, maximum productivity of freshwater for simple model and modification model 3480 and 4600 ml/m2/day respectively.