Abstract: The present invention relates to water based disinfectant formulation comprising Didecyldimethyl ammonium chloride as an active agent, Polyoxy ethylene cetyl steryl as de-foaming agent, Ethylenediamine as chelating agent. Potassium Carbonate as filler pH adjusting agent. Monoethanolamine as neutralizer, and Distilled water as solvent, provides immediate efficacy upon application and prolonged residual activity against broad spectrum of microbes. The formulation forms transparent water soluble film which do not cause any unsightly residues on applied surface, easily removed by warm water, and does not require special treatments and harsh chemicals for its complete removal. The present invention also provides a system and method of preparing disinfectant formulation.