Fact sheet N° 112
(Reviewed) November 1996
WATER AND SANITATION
Every eight seconds a child dies of a water-related disease. Every year more than five million human beings die from illnesses linked to unsafe drinking water, unclean domestic environments and improper excreta disposal.
At any given time perhaps one-half of all peoples in the developing world are suffering from one or more of the six main diseases associated with water supply and sanitation (diarrhoea, ascaris, dracunculiasis, hookworm, schistosomiasis and trachoma). In addition, the health burden includes the annual expenditure of over ten million person-years of time and effort by women and female children carrying water from distant, often polluted sources.
Nearly a quarter of humanity still remains today without proper access to water and sanitation.
During the International Drinking Water Supply and Sanitation Decade (1981-1990), some 1600 million people were served with safe water and about 750 million with adequate excreta disposal facilities. However, because of population growth of 800 million people in developing countries, by 1990 there remained a total of 1015 million people without safe water and 1764 million without adequate sanitation.
Overall progress in reaching the unserved has been poor since 1990. Approximately one billion people around the world still lack safe water and more than two billion do not have adequate excreta disposal facilities. Rapid population growth and lagging rates of coverage expansion has left more people without access to basic sanitation today than in 1990.
Another problem with coverage goals is the magnitude of resources needed to achieve them. At the Global Consultation of Safe Water and Sanitation for the 1990s, held in New Delhi in 1990, it was stated that universal coverage by the year 2000 would require US$ 50 billion per year, a five-fold increase in current investment levels.
In 1992, WHO concluded its monitoring of the Decade with the estimate that a total of US$ 133.9 billion had been invested in water supply and sanitation during the period 1981-1990, of which 55% was spent on water and 45% on sanitation. Urban areas received 74% of the total and rural areas only 26%. Contrary to widespread perceptions, almost two-thirds of all funds were provided by national sources and only a third by external organizations.
WHO estimates that it costs an average of US$ 105 per person to provide water supplies in urban areas and US$ 50 in rural areas, while sanitation costs an average of US$ 145 in urban areas and US$ 30 in rural areas.
Water supply and sanitation can be viewed as a process having three interactive elements. The most fundamental of these elements is the availability of safe drinking water and sanitary means of excreta disposal. This means 20 to 40 litres of water per person per day located within a reasonable distance from the household. Safe water implies protection of water sources as well as proper transport and storage within the home. It also means facilities for bathing and for washing clothes and kitchen utensils which are clean and well-drained. Sanitary excreta disposal is the isolation and control of faeces from both adults and children so that they do not come into contact with water sources, food or people. To break the transmission chain of faecally-related diseases, good standards of personal and domestic hygiene, which begin with handwashing after defecation, are essential.
A second element in the water and sanitation development process is the use and care of water and sanitation facilities. People must use these facilities properly to obtain the health benefits inherent in them. This means knowing how to protect and store water safely, how to maintain personal and domestic cleanliness, how to care for excreta disposal facilities and how to avoid or minimize unsanitary environmental conditions. Knowledge transfer, behaviour change and personal responsibility are the key factors.
The third of the interactive elements is the institutional support from the communities, developing agencies and government policies that provide a framework for water and sanitation improvements. Experience has shown that community-based efforts, whether in a small village or a large metropolis, are most effective in identifying and meeting peoples' needs. Governments, especially at the regional and national levels, are more effective as facilitators of the development process than providers of water and sanitation improvements.
Water contaminated by human, chemical or industrial wastes can cause a variety of communicable diseases through ingestion or physical contact:
Water-borne diseases: caused by the ingestion of water contaminated by human or animal faeces or urine containing pathogenic bacteria or viruses; include cholera, typhoid, amoebic and bacillary dysentery and other diarrhoeal diseases.
Water-washed diseases: caused by poor personal hygiene and skin or eye contact with contaminated water; include scabies, trachoma and flea, lice and tick-borne diseases.
Water-based diseases: caused by parasites found in intermediate organisms living in water; include dracunculiasis, schistosomiasis and other helminths.
Water-related diseases: caused by insect vectors which breed in water; include dengue, filariasis, malaria, onchocerciasis, trypanosomiasis and yellow fever.
No single type of intervention has greater overall impact upon the national development and public health than does the provision of safe drinking water and the proper disposal of human excreta. The direct effects of improved water and sanitation services upon health are most clearly seen in the case of water-related diseases, which arise from the ingestion of pathogens in contaminated water or food and from insects or other vectors associated with water. Improved water and sanitation can reduce morbidity and mortality rates of some of the most serious of these diseases by 20% to 80%.
ESTIMATES OF MORBIDITY AND MORTALITY OF WATER-RELATED DISEASES
1People currently infected.
3Case of the active disease. Approximately 5,900,000 cases of blindness or severe complications of Trachoma occur annually.
4Includes an estimated 270,000 blind.
5Mortality caused by blindness.
Source: WHO data
For further information, please contact, Health Communications and Public Relations, WHO, Geneva. Telephone (41 22) 791 2584. Fax (41 22) 791 4858.
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