Table 6.

Impact pathway linking domestic water supply to food production or purchase

Context	Mechanism	Outcome	Implication for the diarrhoea outcome or its estimation in the study and the Waddington review
Water supply interventions enable beneficiaries not only to avoid water-related diseases but also to access a resource, increasingly in demand, that can be used for a range of purposes.	People often use water for production (esp. of food in rural/peri-urban areas); or to reduce private expenditure for water. The poor use the additional income in large proportion to purchase food. They also save time for procuring water.	Increased food, water and time are valued in their own right. Improved child nutrition may also contribute to reduced diarrhoea.	Attribution of diarrhoea reduction solely to direct effect of water supply may be mistaken; people’s commitment to support and maintain the system is increased, enhancing sustainability (Aziz et al. 1990a,b; Hoque et al. 1996); markedly pro-poor distribution of benefits is unrecognized (Galiani et al. 2008).