To follow up country work supported bythe Public-Private Partnership for Hand-washing (PPPHW), theWorld Bank Water and Sanitation Program (WSP) receivedfunding from the Bill and Melinda Gates Foundation tosupport projects to scale up the promotion of hand-washingwith soap (HWWS) in Peru, Senegal, Tanzania, and Vietnam.The major project objectives of the hand-washing initiativeare: i) inculcate the HWWS habit among millions of mothersand children in these countries; ii) use a strong monitoringand evaluation (M&E) component to enhance theconceptualizing and management of such programs; and iii)establish sustainable programs that will continue and expandafter this four-year grant ends. Enabling environmentassessments were carried out in all four countries to assesscurrent conditions for scalability and sustainability and tomake recommendations for improving conditions that are notsupportive. This report summarizes the study in Tanzania.All of the country studies followed a similar methodology,developed by the WSP, to examine nine dimensions ofscalability/sustainability through individual and groupin-depth interviews and a survey in which respondents areasked to score various statements. The project also engagesother relevant ministries. Planning, site selection,implementation, and capacity building are being done inconsultation with the appropriate government agencies, andthe private sector and civil society are being engaged aspartners. This four-year project (1.5 years of planning, 2years of implementation, and 6 months of evaluation)launched with a group of core partners in December 2006, andis expected to take place in 10 districts. The assessmentmethodology, findings, and recommendations that result fromthis assessment are documented in this report.