Indicator microorganisms are group of bacteria suggestive of possible prevalence of pathogens. It is important to keep in mind that, there is no proven correlation between indicator organisms and prevalence/levels of pathogens, although there is a possibility that, pathogens might be a positive fraction of indicators. Despite this, it can be accepted that the levels of pathogens are lower than the levels of indicators and also decrease in the population of indicators suggests a similar reduction in the population of pathogens. Furthermore, each indicator is correlated to different pathogens and, therefore, more than one indicator should be used