Waterborne diseases such as diarrhea are a major killer in low-income settings, particularly of young children. For those without access to safe drinking water, household water treatment, such as boiling, chlorinating, and filtering water in the home, when combined with safe storage (HWTS) can significantly improve water quality and prevent disease, thereby contributing to the child survival and other health priorities encompassed within the Millennium Development Goals (MDGs). There is uncertainly, however, about whether HWTS should count toward the MDG water target, which promotes "sustainable access to safe drinking water". This paper reviews the relevant research and concludes that it should not. Although HWTS can significantly improve water quality, it does not improve water quantity and access-key aspects of the MDG water target that are essential for optimal improvements in health and development. A policy that excludes HWTS from the MDG water target will discourage governments from diverting scarce public resources from comprehensive and long-term improvements in water supplies. At the same time, the health-oriented MDGs provide a sufficient case for scaling up effective and appropriate HWTS among target populations. Moreover, a health-based strategy for HWTS will help ensure that promotion of the intervention is driven by measurable improvements in outcomes rather than inputs, thus encouraging advances in both hardware and programmatic delivery that will make HWTS more effective, appropriate, and accessible to vulnerable populations.