Imperatives for Wise Water Management From Public Good to Priced Commodity Improving the efficiency of water use is indispensable. In the United States, contrary to all expectations, total water use has declined by 10 percent since 1980, even with population growth and a continued increase in economic wealth. Industrial use has declined by 40 percent from a peak in 1970, while industrial output and productivity have both increased. Similarly, in Japan, where industrial output has soared since the 1970s, total industrial water use has fallen by 25 percent. The potential to reduce industrial use through further innovation, improved technology, and cost incentives is 20-30 percent.
Comparable saving is possible in developing countries.
Readily available means include improving the efficiency of household appliances, better pricing structures, use of recycled water for certain applications, and especially reducing unaccounted-for water due to leaks and nonmetered connections in aging distribution networks. In many cities, such as Dhaka, Jakarta, and Manila, nonrevenue water exceeds 50 percent of water use. The single largest variable in future water use for human needs is irrigation. According to the UN's Economic and Social Commission for Asia and the Pacific, irrigation in Asia and the Pacific accounts for 80 percent of total withdrawals, compared with 70 percent globally. By far the largest share of investments in agriculture during the green revolution era went into irrigation schemes.