Five industries – primary metals, chemicals, petroleum, pulp and paper and food processing – account for two-thirds of water's industrial use, yet water rarely represents more than one percent of their manufacturing costs. For a given unit of output some industrial plants withdraw 5 to 20 times as much water as other plants manufacturing the same product, and the largest amount of this is discharged with varying degrees of thermal, biological or chemical pollution.
Europe and North America are the only regions currently using more water in industry than in agriculture. On current trends, industrial water use will more than double by the year 2025 with a four-fold increase in pollutant emissions to watercourses (WMO and others 1997). In some countries, industrial water demand will rise even more sharply. Industrial water use in China, for example, is projected to increase more than fivefold by the year 2030 (Brown and Halweil 1998).