Water shortage is one of the most worrisome issues around the globe, especially with the increase in the human population. Nowadays, attention has been drawn towards the reuse of greywater because of its large volume and low contaminants. In the present research, greywater samples were collected from different sources including; households, restaurants, mosques, laundries, guest houses and sport clubs in Mansoura city, Egypt. The counts of total coliforms, Escherichia coli, Enterococcus sp.,
Pseudomonas aeruginosa, Staphylococcus sp., Salmonella and Shigella sp. were detected. The results indicated that there were variations in counts of bacterial content in greywater samples collected from different sources and sampling time. Tap water samples generally did not contain any microbial content under this study. However, greywater samples contain high counts of tested bacterial content under different sources, except laundry samples. In addition, restaurant and household samples always contained higher counts of bacterial content compared to the other samples under various locations. On the other hand, the counts of bacterial content
were always higher in July samples, while was lower in January samples as compared to the other months. It could be stated that, such greywater contains significant levels of total coliforms and E. coli in most tested sources which determine its uses. Counts of E. coli in greywater collected from restaurant was the highest risk (531 CFU/100 mL), while in laundry recorded the lowest risk (24
CFU/100 mL). Overall, the study can help strategy makers in formulating biological' guidelines for reuse of greywater and the needed designs for greywater treatment technologies.