Five years after the introduction of the Sustainable Development Goals (SDGs), and with the SDG midterm review approaching in 2022/23 marks a critical point for the WASH sector in Eastern and Southern Africa, with many countries not on-track to achieve the SDG 6 targets. UNICEF, as the lead agency of a multi-partner approach across 21 member states in Eastern and Southern Africa, identified that this point represents a moment for the WASH sector to take stock of progress towards SDG6, understand the gaps in our current knowledge on levels of access, and take course corrective actions to ensure that SDG6 is met in the remaining 10 years to 2030 vision. As part of this broader SDG 6+5 review, UNICEF commissioned ITAD to explore and document the current state of SDG 6 monitoring across all countries in Eastern and Southern Africa. This included a rapid assessment, summarising the status of WASH monitoring systems in all countries; as well as a series of five case studies (of which this is a part) to provide a deeper analysis of the monitoring frameworks and systems, identify the enablers and barriers to strong monitoring systems, and to capture key learnings for the sector and region. Tanzania was selected to further explore the coordination of monitoring in a strongly performing WASH sector, the sector-level routine monitoring systems, and the extent of localization of SDG 6.1 and 6.2 in monitoring systems.