Solar water pumping systems are the ideal energy provider solution especially in rural and isolated areas where the traditional sources of power (electricity or diesel) are unavailable or very costly. It is available with abundant quantities of daily falling solar radiation of about 5.5 kWh/m²/day and considered a clean source of energy. The present work provides a mathematical model and performance evaluation of a solar water pumping system for different water demands through a comprehensive design tool simulation program prepared and designed by the authors. The simulated results can provide for the studied water demand range, the corresponding pump electric power for the desired total dynamic head, the required PV peak power, its related area requirements, and the corresponding total cost of the system components in Euro. The present research is a good accurate quick tool for designers, users, and buyers of such systems.