More than 1 billion people do not have access to safe drinking water. In the developing world, 80% of all diseases are water-related^a. The magnitude of the problem can be seen from the fact that diarrhoeal disease alone leads to 2 - 2.2 million deaths and 4 billion episodes of disease every year^b worldwide. An estimated 400,000^c deaths due to diarrhoeal disease happen amongst children in India every year.

This is an immense economic and social burden on the country. The magnitude of the problem can be further gauged from the fact that in India, 19.2% of all children under the age of 3 years have had diarrhoeal disease in any two week period^d. It is in this context that the United Nations has established the Millenium Development Goal of halving the number of people without safe drinking water, and reducing by two-third the mortality of children under 5 years, by 2015.

What causes waterborne diseases

Waterborne diseases result from the contamination of water by harmful viruses, bacteria and parasites. These microbes find their way into water from faeces - for example, 1 gram of faeces can contain an estimated 10 million viruses, 1 million parasite cysts, and 100 worm eggs^e. This problem of water contamination exists not only in surface water sources like rivers, but also in groundwater sources; and in many cases even where water has been treated because of re-contamination during transmission to consumer homes, and unhygienic storage and handling.

What can be done to solve the problem of waterborne diseases

World Health Organisation (WHO) says that the provision of safe water alone will reduce diarrhoeal and enteric disease by up to 50%, even in the absence of improved sanitation or other hygiene measures^b. WHO further asserts that there is now conclusive evidence that simple, acceptable, low cost interventions which are capable of eliminating harmful viruses, bacteria and parasites from household stored water, can reduce the risks of diarrhoeal disease for people of all ages in both the developed and developing world^b.