A septic tank serves primarily as settling chambers removing solids from house domestic sewage contaminants including microorganisms. In this study 40 of the modified septic tanks were used in five small villages such as El-Raad (6); El-Giara (4); El-Geziera (12); El-Azeba (7) and Dandara (11) in Kena governorate. Microbiological and chemical quality were determined to evaluate the efficiency assessments of these modified systems. Results showed that salmonellae were removed completely in 80 % (32/40) from total samples of the fourth compartment effluents of these systems in different areas. The overall reductions were more than 97% for total bacterial counts and total coliforms and more than 99% for fecal coliform and Escherichia coli. In addition to that more than 99% reduction for fecal Streptococci was obtained in all different areas except El-Raad the removal rate was decreased to 97.7%. The reductions of BOD5 and SS were more than 65% in all areas except El-Geziera where the removal rate of BOD5 was decreased to 55.4%. Density of Escherichia coli was 102-103 MPN/100 mL with the effluent of the fourth compartment which complied with reuse wastewater for unrestricted irrigation according to WHO guideline. Anaerobically treated along the septic tank collected from the fourth compartment is directed to a concrete filtration compartment completely filled with gravels over a soil filtration zone. Samples from the fifth compartment can not be able to collect. In this compartment biological processes such as filtration, adsorption and biological interaction between microorganisms may take place which reduce microbial population by about 1-2 log units.