The securing of an adequate water supply has become one of the most critical problems facing many societies today. Fresh water, needed by human beings to sustain life, health and productive activities, constitutes only 0.8% of the world's total water supply, and it is not known just what portion of this amount is contaminated. Lack of water and ensuing poor sanitation are responsible for disability, disease and death, especially among infants and young children. Women, traditionally the world's water-bearers, suffer particular hardships. The time and energy they consume in fetching water from long distances might otherwise be devoted to caring for their families – or to educational or income earning pursuits of benefit to the entire community.
Of all environmental ills, contaminated drinking water the most devastating in its consequences. Each year 10 million deaths are directly attributable to waterborne intestinal diseases. One-third of humanity labours in a perpetual state of illness or debility as a result of impure water; another third is threatened by the release into water of chemical substances whose long-term effects are unknown.
Global water use doubled between 1940 and 1980, and is expected to double again by 2000. Yet 80 countries, with 40% of the world's population, already suffer serious water shortages. There will be growing competition for water for irrigation, industry and domestic use. River water disputes have already occurred in North America (the Rio Grande), South America (the Rio del la Plata and Parana), South and Southeast Asia (the Mekong and Ganges), Africa (the Nile), and the Middle East (the Jordan, Litani, Orontes, and the Euphrates).
Barely 70% of the urban population in developing countries has access to a water supply: that is, to running water, tube wells, etc. The figure is significantly lower in rural areas, where only 12% of the population has reasonable access to a water supply. Some of the serious communicable and parasitic diseases in the developing countries, affecting millions of people, can be directly related to the water conditions prevailing in their immediate environment; according to a WHO report, about 80% of all known diseases are related to water misuse. A lack of basic sanitation, nutrition, water supply and sewage facilities provokes great centres of infection, which are characteristic of the developing countries.
Chemical pollutants, including pesticides and herbicides also produce water shortage by rendering water unpotable. Some chemicals are highly persistent in water and, unlike 'conventional' contaminants, are not amenable to natural purification. This situation is worse in arid zones, where there is little chance of dilution.
Throughout Africa, water is unevenly distributed by nature and unfairly allocated by man. Many African countries already experience water stress or scarcity conditions. By 2010 over 4000 million Africans in at least 17 water-scarce countries will face severe constraints on food production, ecosystems protection and economic development due to water shortage. The poor majority will likely continue to pay the highest price. They already spend a considerable part of their limited income, calories and time to get inadequate amounts of water. In 1996, over half the population still lacks reasonable access to safe water. Even more lack adequate sanitation.
Many parts of the European Region are well endowed with freshwater resources, but shortage of water may be the most urgent environmental problem some countries face. Throughout the 1990s, the CCEE and NIS have been especially severely affected, suffering from a significant period of reduced investment in water supply in addition to organizational disruption.
Global freshwater consumption rose sixfold between 1900 and 1995 – at more than twice the rate of population growth. About one-third of the world's population already lives in countries with moderate to high water stress – that is, where water consumption is more than 10 per cent of the renewable freshwater supply. The problems are most acute in Africa and West Asia but lack of water is already a major constraint to industrial and socio-economic growth in many other areas, including China, India and Indonesia (Roger 1998). In Africa, 14 countries are already subject to water stress or water scarcity, and a further 11 countries will join them in the next 25 years (Johns Hopkins 1998). If present consumption patterns continue, two out of every three persons on Earth will live in water-stressed conditions by the year 2025 (WMO and others 1997). The declining state of the world's freshwater resources, in terms of quantity and quality, may prove to be the dominant issue on the environment and development agenda of the coming century.
It has been estimated that by 2025 up to 16 per cent of Africa's population (230 million people) will be living in countries facing water scarcity, and 32 per cent (another 460 million) in water-stressed countries (Johns Hopkins 1998). Africa's share of water on a per capita basis is estimated to have declined by as much as 50 per cent since 1950 (Bryant 1994).
In 2000, estimated 1 milliard people worldwide lacked clean drinking water and around 3 milliard did not have adequate sanitation.
In the maquiladora zones of Mexico, water is so scarce that babies and children drink Coca-Cola and Pepsi instead.