Over 1 billion people lack access to improved water sources and 2.6 billion lack access to appropriate sanitation, greatly contributing to the global burden of disease. The international community has committed to reducing by half the proportion of the world's population lacking access to water and sanitation as a part of the Millennium Development Goals (MDGs). However, the disease burden due to poor access, is borne primarily by the poorest countries and the poorest people within them. Simply reducing the proportion of people without adequate access will not automatically result in proportional reductions in the related disease burden. The public health challenge inherent in meeting the MDG targets is ensuring that improvements result in access to water and sanitation for the critical at-risk populations. Innovative approaches are required to ensure the availability of low-cost, simple, and locally acceptable water and sanitation interventions and integrating these approaches into existing social institutions, such as schools, markets, and health facilities.