ABSTRACT
Given the myriad development challenges facing the world's poorest countries and communities—from the HIV/AIDS pandemic to pervasive gender inequality and grinding poverty—why has halving the proportion of people without sustainable access to safe drinking water and basic sanitation services been singled out as critical? The imperative of dramatically expanding coverage of water supply and sanitation services and improving water management overall deserves the vigorous response of the international community because of the relationship between water supply and sanitation, and questions of human health, overall economic development, and equity, and because of humankind's shared understanding of our responsibilities to one another, a common understanding enshrined in many international human rights instruments (box 2.1). Not everyone will find the various rationales for investment in water supply and sanitation listed below to be equally persuasive. What matters is that water supply and sanitation advocates, policymakers, and practitioners are able to articulate to a range of key constituencies a compelling case for action and that governments and other important actors respond with the necessary measures.
