Drinking water situation in developing countries

Almost one billion people do not have access to clean drinking water. Every day, these people drink water that is infected with germs. This often leads to diarrhoeal diseases such as typhus, dysentery and cholera. These kinds of diseases can quickly lead to death, particularly for small children. Every year, more than 1.6 million people die from the effects of diarrhoea. The World Health Organisation (WHO) estimates that 94% of all occurrences of diarrhoeal diseases are avoidable. Research was therefore begun to find out how the application of the SODIS method affects the health of the population.

Less diarrhoea thanks to the SODIS method

In the 1990s, the Royal College of Surgeons of Ireland carried out the first investigation of the effect of the SODIS method on health. The study was conducted in Kenya and showed that 16-24% of diarrhoea-type illnesses and 86% of cholera occurrences were avoided with the aid of the SODIS method.

In 2002 and 2003, the Swiss Tropical Institute studied children in Bolivia. Children who drank water that had been treated with the SODIS method were 70% less likely to suffer from diarrhoea than those who drank untreated water.

The University of Uppsala in Sweden and the Christian Medical College in Vellore, India, studied children in the slums of Tamil Nadu, India. Here too, the frequency of diarrhoea among children who drank water that had been treated with the SODIS method was considerably lower. The rate of diarrhoea occurrences among this group was 40% lower than among their neighbours who drank the water without treatment.

A study by the Swiss Federal Institute of Aquatic Science and Technology (Eawag) found similar figures among children in the slums of Yaoundé, Cameroon. Children in families that treat their water with the SODIS method have a by 42% reduced risk to fall ill from diarrhoea than their neighbours whose parents do not treat their water.

Scientific publications

SODIS method together with washing hands particularly efficient

Not all methods for preventing diarrhoeal diseases are equally effective. A systematic study of various strategies revealed the following picture:

  • Better water at the source prevents 11% of diarrhoea cases
  • Better sanitation facilities prevent 32% of diarrhoea cases
  • Treatment of drinking water in the home (e.g. SODIS method) prevents 39% of diarrhoea cases
  • Washing hands prevents 45% of diarrhoea cases

These results show that, besides methods for treating water in the home, washing hands is the most effective strategy for preventing diarrhoea. We therefore recommend that when introducing a water treatment method, to always discuss hygiene in the home as well.

© SODIS 2020
Last update: 30.08.2011