An improved desalination process which comprises: (a) blending a first stream of softened water having a substantially reduced concentration of hardness ions with a second stream of water containing a higher concentration of hardness ions than the softened water to form a feed to a desalination system, wherein the source of the first and second streams are different, and (b) passing the feed through the desalination system to form a water product of potable quality, wherein the improvement comprises the introduction of a feed of variable proportions of the softened and second stream of water to the desalination system to increase the top operating temperature of the system and increase recovery of potable water.