c configuration by simple switching of manual or automated shut off valves in a predetermined sequence to divert the influent water to the ro membranes as a first step the u201c c u201d subscript in the ro ix c term refers to use of the ix resin to treat the ro membrane concentrate i e as a water softener contrary to the more common use of ix resin as a demineralizing material to remove residual ionic species from ro membrane permeates which will produce a completely demineralized water according to this embodiment most of the concentrate produced by the ro membranes is sent to the ix water softener followed by recycling of the hardness free ro concentrate at a sufficiently high flowrate in the range 25 60 of the influent water combining said ix softened ro concentrate with the influent water and introducing the combined flow into the ro membranes to produce more permeate thereby achieving product water recoveries gt 90 and even gt 95 depending on the tds of the influent water this embodiment can be used to provide purified water for industry and for municipalities especially in locations where surface water or sewer systems are not available or where the water cost is high i e gt.