A World of Water Woes

(page 2 of 3)

Water use in the U.S.

Household uses of water

World water availability

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Industrial and Mining Use Industry and mining account for a relatively small portion of water use, less than 6% of the total in 2000 (23.2 billion barrels per day). However, much of the mining consumption is in areas with very limited water supplies. In addition, the exploitation of shale oil deposits in the American West would require water, again in an area where all the water is already taken up by downstream uses, including agriculture. Recent technological advances in shale-oil processing significantly reduce water requirements, but the potential problem is still there.

Public Water Supply and Household Use Use of water through public water supplies, which serve mostly households and commercial establishments, continued to rise until 2000, but more slowly. From 1950 to 1980, usage rose 3% per year. In addition, there were 3.59 billion gallons per day of self-supplied water (wells), mostly in rural areas. Public water use rose to 43.2 billion gallons per day in 2000, from 34 billion in 1980, and only 14 billion in 1950. Growth has slowed since 1980 but continues to rise 1.2% annually.

Much of the focus on demand management has been on household water use, which accounts for about 5% of total use (about 40% of the public water supply), but more than 10% of the consumptive use. Adding in wells would give another percentage point to the ratio. Agricultural uses are larger and perhaps easier to control technologically, but there are political obstacles to any major changes. Moreover, because farms were there first, the cities have had to control their own use rather than take water away from farmers.

Estimates of how water is used vary from survey to survey. Most of the results, however, suggest that about one-third of household water is used outside the house, primarily for watering foliage, but also for car washing and other uses. In a national study of 12 cities ("Nature of Residential Water Use and Effectiveness of Conservation Programs," BASIN, 1998), outdoor usage accounted for 53% of the total (see chart). Other estimates (from the Environmental Protection Agency) suggest that overwatering wastes about one-half of that.

Indoor water use accounts for about 69 gallons per person per day, mostly in the bathroom, with toilets accounting for 27% of indoor usage and showers and baths 19%. Washing clothes accounts for another 22%. Dishwashers use a low 1.4%. Leaks cost the average household 14% of the water used.

Cities have made important strides in reducing water usage when necessary. In the mid-1980s, for example, Boston faced water shortages as a result of severe drought. By mandating and subsidizing more efficient plumbing and by fixing leaks, the city managed to reduce per capita usage by 31% between 1980 and 2003 (Don Henrichsen, "Water Pressure," National Wildlife Magazine, June/July 2004). New York began a similar program in the early 1990s, saving 70 million gallons per day. Per capita water use in New York City is 60% of that in drought-plagued Los Angeles.

A Patchy Geographical Distribution

Overall, the amount of rain falling in the U.S. is more than adequate, especially compared with the rest of the world. However, fresh water supplies aren't evenly distributed. Lack of water has been and remains a severe problem in the Southwest. Except for occasional droughts, it is not a serious long-term problem in the rest of the country.

The worst water shortage historically for the U.S. was the Dust Bowl of the 1920s and early 1930s. As described in The Worst Hard Time by Timothy Egan, the crisis arose from a period of heavier-than-normal rain in the south-central U.S. Following that was a decade of low rainfall, resulting in devastation of the farms and the region's ecology. A similar pattern has played out in the Sahel region of Africa and in Darfur.

Today's troubles are less the result of the swing in rainfall than of rising populations. Especially in the U.S. Southwest, the growing population base in a year of low rainfall has caused substantial problems.