Summary:

Study on the water quality of the Pisia–Gągolina river, one of the most interesting environmental object, was carried out. Samples of water for chemical research was taken twice a year: winter and in spring. Physical and chemical parameters of water quality were determined in comparison with legal requirement for five quality class of surface water. The most impact on water pollution has concentration of phosphate, dissolved oxygen and amonium. The concentration of dissolved oxygen depended on season and place of sampling. Present level of reservuares water contamination indicates eutrophication of river.