Safe Drinking water is a priority for human health all over the world. Accordingly, the microfauna of raw, filtered, treated, and tap water were investigated in this study. The results proved the efficiency of the Water Plant, but slight occurrence of non-pathogenic bacteria in tap water, indicated the necessity to renovate the distribution system.
Most of the physico-chemical characters are within the standards for drinking water apart from phosphate, nitrate, iron and manganese. Raw water samples only were positive for E. coli, T. & F. coliform, Salmonella and Shigella. This could be referred to the illegal discharge of sewage and other organic pollutants into the water source. Sixty one protozoan genera were identified only in raw water which can be attributed to the influence of chlorination during water treatment. Ciliated protozoan densities proved seasonal variation with highest values during Autumn. Protozoan monthly densities showed significant correlations with certain physical and chemical parameters. Therefore ciliates are considered as bio-indicators for pollution in various aquatic habitats. Simultaneously, rotifers can be used to indicate the performance level of certain stages of water treatment process as they showed significant correlations with different ecological factors.