The objective of this research has been to develop an integrated decision support tool for rural water supply based on Ethiopian case-studies. In order to achieve this objective primary data were collected from 100 rural water supply schemes of three regions of Ethiopia. Secondary data were also gathered on over 36000 rural water supply schemes located in four regions of Ethiopia. These data have been analyzed in order to develop the decision support tools. The author emphasizes that a scheme-based integrated approach is required to ensure sustainability of a rural water supply service. Accordingly, a three-stage scheme based integrated decision support model has been developed. In the first step, two cost estimation equations have been formulated based on exponential and linear regression methods for schemes at spot and with distribution respectively. At the second step, a Multi-Criteria Analysis composite programming tool based on two objectives - planning and physical development and sustainable operation and management of schemes - was designed. Utilizing this tool, nine indexes were determined from aggregation of 53 quantitative and qualitative indicators to select among six alternative scheme types or evaluate existing ones. Integration of indexes shows that among the six types of schemes considered in developing decision support tools, spring with gravity distribution scores the highest sustainability index and a maximum of total evaluation points. On the final third step, system dynamics modeling that predicts the performance of a scheme through time shows that for a given number of beneficiaries, scheme performance highly depends on consumption pattern, population growth, scheme cost, scheme yield, tariff, income of beneficiaries and sustainability index. The author, in availing an integrated model as a decision support tool for planners and engineers has found that the current consumption quantities and tariff models of covering only operation and maintenance cost for rural water supply would not guarantee sustainable and effective achievement of the Millennium Development Goals and national development goals. Therefore there should be a gradual shift from spot sources to schemes with distribution in order to fulfill the required volume of water. A similar step is also necessary to move from a policy of a tariff based only on operation and maintenance cost to that which includes cost recovery. The integrated model clearly demonstrates what could be the effect of increasing or decreasing consumption on key parameters of rural water supply system: scheme yield, health impact, income and long term sustainability. However, further research is required to investigate on how this paradigm policy shift could be realized.