We adopted the Water Framework Directive, therefore we are committed to the sustainable use of water resources. It is also necessary to prevent the deterioration of the water. River basin management plan sets the foundation for achieving appropriate quality of water. When analyzing the availability and use of water it is necessary to determine the current conditions of water areas for further analyses. In this diploma paper we focused on the analysis of the Mirna River Basin, which is with its 44 km the third longest river in Dolenska and belongs to the Sava river basin. It was made an analysis of the current state of availability of water resources and their use.