The solar PV water pumping system for irrigation is a technological innovation that uses more efficient and economical water pumps. Despite all the advantages offered by this technology, many small-scale farmers have had a bad experience of it through the installation of unsuitable or poorly dimensioned systems, and continue to use fossil-fuelled thermal pumps. To alleviate this problem, this study set itself the following objectives: (1) to size and design an efficient solar PV irrigation system on the basis of a sound sizing method, and then (2) to compare its technico-economic performance with that of a gasoline-powered thermal pump for the same service. Sizing was carried out using an analytical method that takes into account the characteristics of the site and the configuration of the pumping system to be installed.