In order to have clean environment and healthy people at rural areas, we have to provide them enough safe drinking water at reasonable distance to dwellings. The more the number of villages in one water supply project, (called village complexes) more qualified engineers can be involved in the design, construction and operaticn, processes. So, naturally better quality of water with reasonable price can be produced.
About 180 of this kind of complexes were surveyed through 72 questionnairs and the collected data were analysed for design criteria and project features. One of the main objective to compute was cost per capita and per cubic meter of water produced. It showed that we have to determine the limit of the number of villages in any complex in order to have the reasonable price.