Why is household water treatment and safe storage an important intervention for preventing disease?
Unsafe drinking water, along with poor sanitation and hygiene, are the main contributors to an estimated 4 billion cases of diarrhoeal disease annually, causing more than 1.5 million deaths, mostly among children under 5 years of age (WHO 2005). Because diarrhoeal diseases inhibit normal ingestion of foods and adsorption of nutrients, continued high morbidity also contributes to malnutrition, a separate cause of significant mortality; it also leads to impaired physical growth and cognitive function, reduced resistance to infection, and potentially long-term gastrointestinal disorders. Contaminated drinking water is also a major source of hepatitis, typhoid and opportunistic infections that attack the immuno-compromised, especially persons living with HIV/AIDS.
Outbreaks of acute watery diarrhoea (AWD) add to the disease burden and require costly diversion of scarce health and other resources to minimize fatalities. Diseases associated with contaminated water also exact a heavy economic load in the developing countries, both on the public heath care system for treatment and on persons affected for transport to clinics, medicines and lost productivity. They also adversely impact school attendance and performance, particularly for girls and young women who must care for and assume the duties of ill parents and siblings.
As part of its Millennium Development Goals, the United Nations expressed its commitment by 2015 to reduce by one half the people without sustainable access to safe drinking water. Current estimates are that there are still 1.1 billion people without this access (WHO/UNICEF 2006). Considerable progress is being made in expanding the coverage of “improved water supplies” such as protected wells and springs, boreholes and household connections. However, results from a recent assessment in six pilot countries, found that 31% of drinking water samples from boreholes exceeded WHO guideline values (GV) and national drinking water standards in the pilot countries for faecal contamination, the leading source of infection and disease (Rapid Assessment of Drinking Water Quality -RADWQ 2006). At the household level, contamination of stored water is even more common. In one of the pilot countries, only 43.6% of samples from stored water were in compliance with the WHO guideline value and national standards, and more than half of household samples showed post-source contamination. This is consistent with a large body of research world wide that has shown that even drinking water which is safe at the source is subject to frequent and extensive faecal contamination during collection, storage and use in the home (Wright 2004).
Treating water at the household level has been shown to be one of the most effective and cost-effective means of preventing waterborne disease in development and emergency settings. Promoting household water treatment and safe storage (HWTS) helps vulnerable populations to take charge of their own water security by providing them with the knowledge and tools to treat their own drinking water. This document summarizes some of the leading approaches for treating water in the home, provides evidence of their effectiveness and cost effectiveness in development and emergency settings and it outlines how promotion of HWTS can be incorporated with UNICEF programmes.