We propose a novel method for dramatically increasing the flux by chemically modifying the surface of commercially available thin film composite reverse osmosis membranes. SW30HR (Filmtec) membranes show a large increase in flux, up to an order of magnitude, with no decrease in ion rejection properties on treatment with hydrofluoric and fluosilicic acids. Surface studies by scanning electron microscopy and X-ray photoelectron spectroscopy revealed significant morphological and chemical changes in the active skin layer of the chemically treated membrane compared to that of the fresh (unexposed) membrane. The surface treatment method proposed here may have significant implications for the development of high flux reverse osmosis membranes in the future.