Nano particles of Zinc Oxide has received much attention due to their unique antibacterial, antifungal, UV filtering, catalytic and photo-catalytic activities. The Nano particles of Zinc Oxide are synthesized through a simple and novel technique using aqueous solutions of metal acetate and carbonate. An organic templating agent (EDTA) is used in this work to prevent agglomeration. The carbonate precursor obtained is heated on the basis of TGA to obtain the metal Nano composite. The effects of different parameters on particle size and morphology of ZnO powders is optimized by ÂÂone at a timeÂÂ method. Under optimum conditions, spongy shaped, uniformed and homogeneous nanostructured ZnO nano powders with particle size few nm are obtained. The structural characterization of the nano powders are done using the X-ray diffraction and electronmicroscopy techniques. The optical characterizations are done using UV-Vis spectroscopy, FTIR and photoluminescence studies. The effect of Zinc oxide nanoparticles on the growth of few common water pathogens are studied to explore its use as antibacterial agent to be used in water purification. To understand the mechanism of antibacterial activity and to confirm the role of reactive oxygen species the samples are annealed at different temperatures and the microbial activity is probed.