Shit Flow Diagram

A shit flow diagram (SFD) is a visual planning tool that maps how human waste flows through urban sanitation systems, using color-coded arrows to distinguish between safe and unsafe management practices. Developed for use primarily in low- and middle-income countries, SFDs help identify specific points in the sanitation chain requiring intervention by showing the relative scale of safe versus unsafe excreta handling across containment, transport, treatment, and disposal stages. While valuable for sanitation planning and policy development, the accuracy of SFDs can be limited by data reliability issues, though methodological improvements continue to address these constraints.