The present study was carried out to evaluate heavy metals residues in water and fish (Oreochromis niloticus) tissues collected periodically from summer 2007 to spring 2008 of different water sources (agricultural drainage water, mixed drainage water, and fresh water), while there were no fish could be found in mixed drainage water. There were significant differences among different water sources as well as different seasons. Water samples had Fe residuals level exceeding the permissible limit in all different water sources while Pb level exceeding the permissible limit in mixed drainage water in spring season. Bioaccumulation of Fe, Zn, Cu, and Cd varied in muscle, gills, and liver tissues of Oreochromis niloticus. Generally, it could be mentioned that heavy metals concentrations in different investigated fish organs were in the following order: muscle < gills < liver. Lead concentrations were not detectable in different tissues of fish collected from different sources during different seasons. The higher values of metals were detected in fish collected from the agricultural drainage water. Moreover, there were seasonal variations had been observed, where cadmium residuals level had exceeding the internationally permissible levels in winter and autumn.