Water restriction and the Geographical location of Iran in dry and semi-arid regions always has been a thread to provide its drinking and agricultural needs while industrial consumptions would be added. Rainfall measurement in Iran (250 mm) in comparison with average rainfall on planet earth (860 mm) defines that its average is less than one-third of earth average. In most of the cities, that don’t have enough water for their basic needs, in cause of low population density, we could have an easy observation which mankind is farming 5 to 20 times more than its water capacity. So there could be harvesting possibility in non-used farmlands. In Isfahan, because of lack of water resources, its dry and semi-arid region and also futurist drought, having an intellectual management of water resources plays an important role. In that case while we are facing lack of water resources in our state, we would have no possibility to increase our water base cultivation. Thus, in such situations we are in need of using creative and practical methods of water management, so we can optimize our usage and benefits.Development of rainwater harvesting systems could make an advantage in increment of half-water cultivation usage. We could use the rainwater harvesting systems in all urban and village texture landscapes. Using rainfall water resources are defined as its non-hardness water add no need of purification. So it looks like an urgent situation to construct principle rainwater harvesting systems.As we had no water management plans in Isfahan, we should initiate our research programs to make its own plans. With that purpose rainfall layers, soil texture, soil depth , land use and its slope have been inputted in ARC GIS software and after valuation of every single elements above, the potential regions of proper rainwater harvesting are defined.The final planning of 5 principle regions on harvesting map are known as Most Desirable, Desirable, average, poor and very poor, in which 2.3 % of whole state area is categorized as 1 st priority, 31.5% of whole state area is categorized as 2 nd riority, 46.4 % of whole state area is categorized as 3 rd priority, 13.6 % of whole state area is categorized as 4 th priority and 6.2 % of whole state area is categorized as 5 th priority. Keywords : Rainwater harvesting , Water resources, Isfahan, ARC GIS, Potential regions.