This study aimed to produce modified granular activated carbon (GAC) by low concentrations of silver (Ag) and/or copper (Cu) nanoparticles with antibacterial capacity for application in water purification. Modified porous materials were produced from the vacuum impregnation method, at the concentrations (mass of metal/mass of activated carbon) of Ag 8 x 10(-4) g/g (Ag 0.08 %), Cu 1 x 10(-2) g/g (Cu 1 %), and Ag 8 x 10(-4) g/g + Cu 1 x 10(-2) g/g (Ag 0.08 % Cu 1 %). The reduction of the metal salts in NPs of Ag and Cu in their metallic forms or oxides was carried out by the thermal decomposition method. The characterization of the produced porous material was performed by x-ray diffraction, programmed temperature reduction, scanning electron microscopy, x-ray dispersive energy spectroscopy, electron transmission microscopy, and specific surface area measurements: Brunauer, Emmet, and Teller; micropore area (t method); pore size distribution (DA method); and volume and diameter of micropores (HK method) and mesopores (BJH method). In the structure of the material produced, Ag and Cu metal compounds and AgO and CuO oxides were identified, with average crystallite sizes of < 60 nm. The efficiency of the inactivation of Escherichia coli was more significant in the GAC modified with the combination of NPs (GAC/NP-AgCu) (6.4 log(10) units), evidencing the synergistic effect of the metals when compared to GAC/NP-Ag (0.56 log(10) units) and GAC/NP-Cu (1.31 log(10) units) modified porous material. Thus, these antibacterial materials can be used for application in water purification, improving the bacteriological quality of water intended for human consumption, noting that the low concentration of metals used can provide exceptional process efficiency.