Water-borne diseases have been estimated to cause more than two million deaths and four billion cases of diarrhea annually. Water-borne pathogenic organisms include bacteria, protozoa, and viruses. Heavy metal contamination of water is also a potential threat to human health. This study aimed to detect contamination of potable water with protozoal and bacterial pathogens as well as heavy metals in Gharbiya governorate in the middle of the Nile Delta, Egypt. Therefore, this study was conducted on water samples from 3 different localities in Gharbiya governorate throughout the year 2014. Water samples (108) were collected from source, plant and tap water at the four seasons. Parasitological, bacteriological, and toxicological evaluation was carried out for all samples. Parasitological evaluation was done to detect protozoal contamination by conventional diagnostic staining techniques, immunofluorescence assay, and flow cytometry. The study identified the protozoal contaminants in water, and showed that flow cytometry positive results were more than the conventional staining. Also, the study identified bacterial fecal contamination of source water as well as heavy metal pollution in source water. Since the integration of flow cytometry could facilitate detection of Giardia cysts and Cryptosporidium oocysts in water samples, we strongly recommend its use as a routine for the detection of these pathogenic protozoa. Finally, Ongoing evaluation of drinking water is needed as well as formulation and implementation of an integrated plan to limit the contamination by pathogens and heavy metals. (C) 2015 Production and hosting by Elsevier B.V. on behalf of Cairo University.