The present report summarizes theevidence and findings from a series of studies and new datacollection around water supply, sanitation, and hygiene(WASH) and poverty. This WASH poverty diagnostic wasundertaken to increase our understanding of the linkagesbetween monetary poverty and WASH services. The work focuseson answering four questions: who are the poor?, does accessto WASH vary by poverty level?, what are the synergiesbetween WASH and other sectors, and how does this affectwelfare?, and what are the constraints to service andpotential solutions to providing universal access to safelymanaged water supply and sanitation? Although the work donein the context of this diagnostic covered both urban andrural areas, the main focus has been on the rural, andparticularly, the indigenous areas, as these are the onesfacing the greatest gaps in services. A more in-depthexploration of urban issues has been left for a future date.