The Bottleneck Analysis Tool makes the WASH sector more effective, by offering practical proposals to achieve sustainable and equitable outcomes and thus facilitating dialogue with financers. CSF developed an initial version of the tool in 2012, on a Microsoft Excel platform, and piloted the tool in workshops in Sierra Leone. After further piloting in 15 countries to assess the tool’s usefulness and ease-of-use and to collect feedback, CSF collaborated with UNICEF in 2015 to develop WASH BAT 2.0, a web-based version of the tool. Significantly more user-friendly and accessible than its spreadsheet predecessor, the tool also offers simplified data analysis and enhanced visualizations. UNICEF has initiated a global roll-out of the tool, and identified enhancements for a tentative upgrade of the tool.