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Global replenishment of accessible fresh water supplies is equivalent to 1,800 m(3)/person/y, some 50 times the recommended VMO standard for human needs. However, distribution of rainfall is uneven, and the timing unpredictable. Many countries now face or will be experiencing water supply and quality problems. This paper reviews the status of selected water-rich and water-poor countries with respect to renewable fresh water resources in order to delineate the scale of the problem. One solution for many water-poor countries is the conversion of saline water to potable water through desalination. Large-scale desalination for industries and urban centres has become a marketable technology over the last three decades. However, the marketplace has not inspired similar developments in small-scale desalination technology for smaller, and particularly, remote arid areas.