The purpose of this work is to show the maximum area for which PV systems are efficient in relation to the most efficient
traditional power system, a diesel pump. The diesel pump has been compared with new power systems at locations relatively far from the power network Kenna and Gillett 1985; Barlow et al. 1993; Posorsky 1996; Frische and Lenz 2000. Precisely for this reason, the information on maximum area that can be economically irrigated by a PV pumping system Amax is an important practical element for planning, i.e., for designers, constructors, managers, and users of the irrigation system. This work will analyze the problem of defining the economically acceptable irrigation areas for two different regions of continental and coastal Croatia, Fig. 2. However, these areas belong to the European
continental Osijek and Mediterranean Split regions. The objective is to show how and to what extent certain factors influence the defining of economically acceptable areas *Amax* and methodology which can be used for such estimations.