Did You Know?

• The adult human body is about 50 to 65 percent water. A child’s body is approximately 75 percent water. The human brain is about 75 percent water.
• While the human body can live for weeks without food, it can only survive a few days without water.
• 220 million urban residents in the developing world lack a source of safe drinking water near their homes.
• Ninety percent of urban sewage in the developing world is discharged into rivers, lakes, and coastal water ways without any treatment.
• Agriculture consumes 60 to 80 percent of the fresh water resources in most countries, and as much as 90 percent in others.

Access to safe water is measured by the number of people who have a reasonable means of getting an adequate amount of water that is safe for drinking, washing, and essential household activities, expressed as a percentage of the total population. It reflects the health of a country’s people and the country’s capacity to collect, clean, and distribute water to consumers.

Water is essential for life, yet in 1995, more than one billion people in low- and middle-income countries—and an additional 50 million people in high-income countries—lacked access to safe water for drinking, personal hygiene and domestic use. These numbers, as Chart 1 shows, represented nearly 25 percent of the world’s 5.7 billion people. In addition, close to 2 billion people did not have access to adequate sanitation facilities.

What is "safe" water and why is it important?

Safe water includes treated surface water, as well as untreated but uncontaminated water from sources such as natural springs and sanitary wells. On average, a person needs about 20 liters of safe water each day to meet his or her metabolic, hygienic, and domestic needs. Without safe water, people cannot lead healthy, productive lives. For example, an estimated 900 million people suffer—and approximately 2 million die—from water-related diarrheal illnesses each year. Most, but not all, of these people live in low- and middle-income countries, and those at greatest risk are children and the elderly. Millions more people worldwide suffer from other water-related diseases, such as bilharzia, cholera, elephantiasis, and hookworm.

Improvements in water supply and sanitation tend to lead to improvements in people’s health and the quality of their lives. Chart 2 shows the results of improvements in water and sanitation service upon the life expectancy of people in three French cities during the 19th century. Throughout history, when people have had an adequate supply of safe water and have been able to practice good hygiene, they have been healthier and have had a better chance of living longer.

Access to safe water is critical to economies and ecosystems, too, and a scarcity of safe water can directly affect long-term prospects for sustainable development. Without an adequate water supply, factories that depend on water may have to close temporarily; crop yields may decline; sick workers may be unproductive; fisheries may be destroyed. The destruction of aquatic life not only cuts into the economy, but also damages the ecosystem. In addition, lack of a reliable system of piped water can prompt people to sink their own wells and deplete the fresh water supply. Air quality can also be affected by shortages of safe water. When people boil household water to kill dangerous bacteria, the fuel they burn can pollute the air. And when they use wood or charcoal as their source of fuel, forests can be destroyed causing additional environmental problems, including erosion and loss of top soil.

Safe water is becoming scarce

Aside from the fact that some regions of the world are naturally arid, the increasing, often competing demands for water are cutting into the global supply. Many rivers and watersheds are polluted by industrial, agricultural, and human waste products, while others are drying up because people are using the water faster than nature can replenish it. In areas with heavy rainfall or irrigation systems, people may waste water because it seems plentiful or cheap, ignoring how much it costs to treat the water after it is used.

Getting water is more difficult—and often more expensive—for the poorest people. In rural areas of developing countries, many women and children spend hours—in extreme cases up to six to eight hours—each day hauling water from rivers or wells. In cities, the poor often do not have water piped to their property; instead, they must buy or take water from other sources. Chart 3 illustrates an example of where people living in an urban metropolitan area in a developing country get their water, showing that only about a third of the population has water piped to either their home or yard. People buying water from other sources may have to pay three to ten times what piped water costs in an area.

Moreover, the rapid growth of cities throughout the world can strain the capacity of governments to provide adequate sanitary facilities, leaving inhabitants, especially the poor, to live amid unhealthy open sewage ditches. Untreated sewage also tends to contaminate the water reserves closest to the cities, forcing communities to pipe water from further and further away as cities expand.

Industrial countries also are increasingly concerned about water quality and availability. Although these countries have stronger economies and greater capacity to collect, clean, and deliver water to citizens, per capita water consumption can be high as people wash cars, water lawns, and turn deserts into farmland, towns, and cities. They spend enormous amounts of money cleaning up water polluted by industrial waste, energy production, agriculture, and households.

The realities of supply and demand

Ensuring that people have an adequate supply of safe water involves an often complex mixture of social, economic, and environmental issues. In recent years, people, industries, farmers, and governments have begun to acknowledge that water is an economic good, not a "free" limitless resource. And as an economic good, there is a wide range in the quality and level of water delivery and sanitation services that people want and are willing to pay for.

Experience from around the globe shows that when people, even the poorest, have a choice in the quality of their water supply and sanitation services, they often are willing to pay a higher price to get higher quality. For example, people who are unwilling to pay for operating and maintaining low quality handpumps and pit latrines may be willing to pay more to get a basic system of piped water and sewers that works fairly and efficiently.

On the other hand, households and industries are not always willing to pay for higher quality services if they feel that what they are receiving is already good enough. For example,some coastal communities in the United States have refused to pay for what they perceive to be unnecessary and expensive sewage treatment even though it is required by federal law for environmental protection. In the end, it appears that when members of a community—households, factories, farmers, and businesses, together with scientists and policy makers—all participate in making decisions about the most feasible system of supplying safe water and sanitation, everyone tends to be more satisfied with the quality and price of these services.

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