A composite polyamide reverse osmosis membrane and method of producing same. In a preferred embodiment, the membrane is made by coating a porous polysulfone support with an aqueous solution containing 2 wt % m-phenylenediamine (MPD), and 0.1 wt % di(ethylene glycol) hexyl methyl ether. Next, the excess solution is removed, and the coated support is dipped in 0.1 wt % organic solvent solution of trimesoyl chloride (TMC) in a mixture of alkanes having from 8 to 12 carbon atoms. After draining the TMC solution off, the resulting composite membrane is air dried and then rinsed in a basic aqueous solution. The resultant membrane exhibits a flux of 21.3 gfd and a salt rejection of 98.9% when used at 225 psi for an aqueous solution containing 2000 ppm of NaCl.