Water is essential to life and water-borne bacterial infections can be a major public health problem. The aim of this research was determination of microbiological quality of different water types within the area of Zadar. Three types of water were used for this research water: an underground water, a surface water and a rainwater. Microbiological determination was performed with indicators of fecal contamination-total coliforms, fecal coliforms, enterococci, E. coli and C. perfringens. The detection and number of the mentioned bacteria was proven by the membrane filtration method. The number of aerobic mesophilic bacteria was determined by inoculation on yeast extract agar. The results showed that total coliforms and enterococci were present in all 4 water samples, while the presence of E. coli was demonstrated in the rainwater collection system and groundwater. The presence of C. perfringens has been demonstrated in groundwater. From the results it was noticed that the most common source of pollution of the analyzed waters is fecal pollution. Aerobic mesophilic bacteria increased in large numbers at a temperature of 22 ° C in all 4 water samples due to more favorable conditions. According to Pravilnik o parametrima sukladnosti i metodama analize vode za ljudsku potrošnju N.N. 125/17, all 4 water samples are not suitable for drinking. Healthy drinking water is one of the major challenges of the 21st century. Financial resources should be devoted to a better understanding of the ecology and behavior of human and animal fecal bacteria in environmental waters.