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

Photo 1.

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.

Chart 2.

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.