Populations located in peri-urban areas are often resigned to using groundwater and surface water as sources of drinking water without, however, worrying about their quality. In order to assess the quality of these waters, a study was carried out in the peri-urban area of Ngoumou. For this study, three sampling stations in the Ebongo stream and three wells were selected. Several physico-chemical variables coupled with biological variables were used to determine the quality of these waters. The analysis of the physicochemical variables reveals that these waters are acid, weakly mineralized and relatively well oxygenated. For biological analyzes, three biological components were used: bacteria, ciliate protozoa and benthic macroinvertebrates. Bacteriological analyzes show that these waters contain bacteria of fecal origin. A total of 698 ciliate individuals belonging to 3 classes, 7 orders and 19 families were harvested. The calculated Shen and Jiang biotic index shows a degradation of water quality from upstream to downstream. Concerning benthic macrofauna, 968 individuals belonging to 3 branches, 4 classes, 7 orders and 25 families were recorded. The Hilsenhoff biotic index reveals that the watercourse is of average to good ecological quality and degrades from upstream to downstream as a result of inputs from runoff and agricultural inputs.