When the demand of fresh water does not exceed a few cubic meters, the solar still is a viable option. Productivity enhancement for this process was one of the main goals of the researchers. In this work, the effect of using the floating perforated black plate on the productivity process is investigated theoretically and experimentally at different brine depths under the same operating conditions. A mathematical model is developed to calculate the theoretical productivity of the solar still with the floating perforated black plate. Two experimental still units of 0.25 m² each are constructed. Comparison between the theoretical and experimental results is considered. In this work, it is found that the results of the developed mathematical model are in good agreement with the experimental results. Also, it is found that using the floating perforated black aluminum plate in the solar still increases solar still productivity by 15% (at brine depth of 3 cm) and 40% (at brine depth of 6 cm.).