Minimum satisfactory quantity and quality of urban domestic water supply in developing countries

Urban water supply schemes in developing countries are often based on high Western standards of quantity and quality. Since developing countries have limited resources this results in fewer schemes and lower population coverage. The worst sufferers are the millions of urban poor and rural dwellers. This thesis investigates the possibility of adopting lower levels of service for urban areas in terms of both quantity and quality in order to serve more people with the same resources. An idealized model represents domestic water use as a function of twenty-three economic, physical, social, technological, geographical, cultural and religious factors. Consequently the demand for domestic water should be determined locally instead of directly adopting any borrowed standard. A procedure is outlined for determining it. A study of domestic water use by a family in Britain leading an Asian way of life indicates a per capita use of 72 litres per day. An extensive review of literature on water and health suggests that the supplied quantity of water should be sufficient to meet all the basic domestic needs including laundering in order to prevent people going to polluted sources. Health benefits appear to be significant with house connections. Water supply is not the only necessary input for improving health. Otner important inputs include safe excreta disposal, health education and proper nutrition. While water quality is important for classical water-borne diseases, water quantity appears to be more important for diseases like shigellosis and infections of skin and eyes. Developing countries should adopt flexible water quality goals based on an appraisal of the prevailing disease patterns and bacteriological quality of water should receive the priority. Outbreaks of diseases due to poor chemical quality are rare. The dangers of nitrate seem overstated. The presence of certain trace elements in drinking water' can partially satisfy the body's daily needs of mineral nutrients. Domestic metering, conservation oriented pricing and community participation are considered in detail and are suggested as suitable means of avoiding wastage, limiting high per capita consumption and conserving water.