Wastewater originating from any source in the residence except for the toilet is defined as graywater. If graywater is treated appropriately, it can be used as reused water. However, wastewater reclamation carries certain health risks, and hence this study is an analysis of pathogenic microorganism and microbial communities in treated graywater for the reuse of water treated by MBR. To reuse graywater, MBR system of a lab scale was constructed with sediment, anaerobic, anoxic and oxic reactors. In the oxic reactor, a submerged MF (pore size is 0.45 mu m) membrane was installed to maintain activated sludge biomass. For the quantification of pathogenic organisms, a standard spread plate method was modified using the selective medium plates. Analysis of 16S rDNA was conducted to detect microbial community. Pathogenic microorganisms such as Escherichia coli, Coliform. Staphylococcus aureus and Salmonella were detected in effluent. According to analysis of phylum and class levels, species of microorganism become simplified through membrane. This suggests that the MF membrane in the MBR system could not perfectly remove microorganisms and further research in diverse pathogens is needed for wastewater reclamation. (C) 2009 Elsevier B.V. All rights reserved.