YALE UNIVERSITY hanced and services expanded through greater collaboration between the fields of water and sanitation engineering and public health. Second, researchers should focus on the sustainability of water and sanitation services by developing strategies that holistically address the influence of the environment, culture, and economics on the implementation and long-term maintenance of treatment systems. Lowcost household technologies, as opposed to centralized systems, offer one means of addressing water and sanitation needs in a more integrated and sustainable manner. Third, the obstacles to improving water and sanitation services, such as lack of investment, lack of political will, and difficulty in maintaining services, must be overcome so that these services can be improved and global coverage ultimately achieved. This will require greater collaboration among the water, health, and education sectors in conducting community-based research and work, formulating evidence-based policies that allow for effective investments, and focusing on developing solutions that can be locally managed and maintained.