This paper presents a theoretical analysis of a low-cost solar water distillation device that operates solely on solar energy, without any electrical or mechanical input. Computational fluid dynamics (CFD) simulations were conducted using ANSYS Fluent software to investigate the performance and potential improvements of the solar still. The study focused on a “basin” type solar still with a transparent inclined cover. By decreasing the coverage angle and internal volume of the still, the productivity of distilled water is improved due to reduced thermal inertia and better-organized convective flow. The final design achieved a daily production of two-thirds of a liter of distilled water per square meter using inexpensive materials and simple construction. The research underscores the device’s viability as a low-cost water distillation solution, offering potential benefits for regions with limited access to clean water. However, the distilled water is not intended for human or animal consumption. Future research aims to practically validate the concept and assess the chemical safety of the distillation process when dealing with polluted water.