Water is a tasteless, odourless and colourless fluid which represents one of the basic conditions for life. Water quality, which represents the presence of individual indicators of a particular substance or energy, is a criterion for determining the basic classification of water use. In order to test the quality of bathing water, data are collected through a continuous process of surface water monitoring. The quality of bathing water depends primarily on microbiological indicators, i.e. on the amount of Escherichia coli and intestinal enterococci. The testing of bathing water quality was conducted at 19 sampling points at two locations in the city of Zagreb (Lake Bundek and Lake Jarun). In order to examine the relation of the amount of microbiological parameters (E. coli and intestinal enterococci) to sampling points ANOVA statistical method was used. Excel was used for calculating parameters of one-factor analysis of variance, which determined that there was no statistical correlation between microbiological parameters and sampling points at lake Jarun, whereas at lake Bundek there was a correlation at one location. Given that a number of results indicate that there is no correlation between microbiological indicators and sampling points, it is very important to conduct regular sampling and analysis of water quality, which enables swimmers to enjoy swimming and reduces the probability of forbidding swimming due to poor water quality.