The paper covers the analysis of water management problems in the cross-border reservoir basin of Bukówka, located at the Bóbr river, at 271+540 km of its course, below the Czech-Polish border, in Dolnośląskie Voivodeship. The problems of water management in the context of the reservoir’s functions have been analyzed; these are: flood control, the provision of water during low water level periods for the Water Treatment Plant in Marciszów, the provision of drinking water for the city of Wałbrzych as well as the provision of proper flow in the Bóbr river bed downstream from the reservoir. Due to its localization right below the border with the Czech Republic, the reservoir is exposed to a number of problems. The study has found that the main problems of water management in the basin area included unsatisfactory state of water and wastewater management in the basin, unsatisfactory state of the surface water quality in the basin area of the reservoir, poor condition of streams and drainage ditches, improper arrangement of arable lands and large downslopes and a lack of monitoring stations on tributaries of the reservoir. It has been found that the hydrochemical conditions in the Bukówka reservoir’s section are unfavorable for it. From the eutrophication point of view, the water flowing into the tank is characterized by a large content of nutrients, especially nitrates, phosphates and BOD₅. In order to counteract eutrophication it is necessary to lower the concentration of nutrients in the water flowing into the tank. One of the basic ways to do so is to restore the water and wastewater management in the reservoir’s basin. Studies in the Bukówka reservoir provide important information concerning the state of the purity of the water supplying the reservoir. In order to obtain accurate information on the state of purity, a monitoring of hydrological and water quality should be continued. The studies are a part of the strategy of protection of the quality of transboundary waters, proposed in the Convention on the Protection and Use of Transboundary Watercourses and International Lakes of 1992.