The need and importance of studying the water regime in higher and mountainous areas, as well as hypsometric zoning are extremely large in regional and spatial planning. The aspect of spatial regionalization has enabled the understanding of the distribution of water in the basin itself. Based on that, a wider picture of the state of this distribution was obtained in some regional units. Getting involved in solving issues related to gaining values of the river regime’s certain elements by hypsometric zones in the Una basin, the basic parameter which it was started from, was determining the value of precipitation amount. For assessment of flow and specific outflow and height, the relation has been applied: precipitation – elevation – area of hypsometric zones – evapotranspiration. Depending on the area they occupy, in the structure of specific outflows and flows, one can clearly distinguish three zones, up to 400 m altitude, the second hypsometric zone from 400 m up to 1400 m, and the third zone above 1400 m altitude. To determine the water height distribution, there have been used the hypsography of the basin and regional specific outflow dependence on average elevation of the basin. Processing all parameters relevant for studying in this paper is done in the ArcGIS software package. The obtained results of this research are very important and can be applied for the needs of agriculture, water management, urbanism and tourism of this part of Bosnia and Herzegovina.