This study investigates the application of 8% and 10% manganese-doped copper (II) oxide nanoparticles (MDCN) for treatment of contaminated water infested with Salmonella specie, Staphylococcus aureus, lead and cadmium ions. 8% and 10% Mn-doped CuO nanoparticles were synthesized using the co-precipitation method, and their physicochemical properties were characterized using scanning electron microscopy (SEM), X-ray diffraction (XRD), and Fourier Transform Infrared Spectroscopy (FTIR). The antibacterial activity of both nanoparticles was evaluated using a turbidimetric assay.