Glass solar stills were tested to see how water depth affects productivity. Single basins produced more during heating, while double basins were better during cooling. Double basin stills outperformed single basin stills overall. Productivity was highest at a water depth of 1 cm. Insulated stills were more productive than uninsulated ones. Double basin insulated stills at 1 cm water depth had 17.38% higher production than single basin stills.