This study aims to compare different sources of water in Dakahlia governorate whether tap or underground water and to assess the sources of such water in terms of microbiological and it detects the classical and new indicators of water pollutants, as well as the detection of certain pathogens, and then isolate and identify some of these pollutants. The samples were collected from six different cities from six areas namely; El-Mansoura, Aga, Met-Ghamer, El-Sembelaween, Belqas and El-Mansala in Dakahlia, Egypt during four season; winter, spring, summer and autumn at 2006/2007. Total bacterial count at 22°C, at 37°C, total coliform, faecal coliform, faecal streptococci, total yeast, candida spp., Aeromonas hydrophila, acid fast bacteria, staphylococci, Salmonella spp., total vibrio spp. and Listeria monocytogenes were studied.