Drinking Water

Of all the uses of water, drinking water is the most fundamental, since the lack of safe and sustained water to drink is life-threatening. Yet, according to the United Nations (UN), as of 2002, nearly 20 percent of the world's population still lacked regular access to clean drinking water. Of these 1.1 billion people, 65 percent were in Asia, 27 percent in Africa, 2 percent in Europe and 6 percent in Latin America and the Caribbean.

In most countries, the state is responsible for the provision of drinking water. Any drinking water supply system consists of three major elements: source (surface water sources such as lakes, rivers, and reservoirs, as well as groundwater sources such as wells), treatment (e.g., adding disinfectants such as chlorine), and distribution to users (including pricing). Drinking water supply systems have had a long history; for instance, the ancient Greeks and Romans were among the first to introduce longdistance water pipelines. However, in recent times, the question of provision of drinking water has become even more critical and complex, particularly with the growth of large cities that are situated at a considerable distance from adequate and reliable sources of water.

How much water people need for drinking varies according to diet, climate and the work they do. The minimum amount of water needed for drinking ranges from about 2 liters in temperate climates to about 5 liters per day for people in hot climates who have to carry out manual work. Pregnant and breastfeeding women need more water. Water for basic needs goes beyond water needed for survival; it includes water for cooking and to maintain a standard of personal and domestic hygiene that is sufficient to maintain health.

Apart from the quantity requirement, drinking water also needs to meet certain minimal quality requirements. Drinking water can be contaminated by a range of chemicals (lead, arsenic, benzene), [Page 486]microbes (bacteria, viruses, parasites), and physical hazards (glass chips, metal fragments) that can pose risks to health if present at high levels. Consuming such contaminated water can lead to waterborne diseases like diarrhea, cholera, typhoid and dysentery, and is one of the leading causes of illness and death in the developing world. The World Health Organization has put in place norms on water quality, which form the basis for regulation and standard-setting in many national, regional and local laws. However, standards for drinking water quality continue to be either ill-defined or poorly implemented in many countries.

For drinking water to be secure and useable, everyone must have safe and easy access to water facilities.

The question of quality of water is also closely related to the question of sanitation. This is because one of the primary causes of contamination of water is the inadequate or improper disposal of human (and animal) excreta. Meeting adequate levels of sanitation is critical in order to ensure that drinking (and other) water meets certain quality standards.