In June, E. coli concentrations reached 7,000 and 16,000 cells per litre for Tbilisi Sea and Turtle Lake respectively. E. coli concentrations obtained for Lake Lisi were above the permitted limit (5,000 cells per litre) for the five samples, while for Tbilisi Sea and Turtle Lake they exceeded the limit value in June. Illegal discharge of untreated waste waters into the water bodies and poor maintenance of recreational zones are the major reasons for the high concentration of bacteria in the lakes and reservoirs of Tbilisi.