This journal article, published in Journal of Environmental Engineering, presents a study of remotely convened WASH sector experts in a multi-round Delphi survey to coalesce sector knowledge on the use of systems approaches for WASH service delivery in low-income countries. The study findings, compiled by the Sustainable WASH Systems Learning Partnership (USAID/SWS), highlight sector alignment on many of the attributes that make WASH systems approaches distinct from traditional approaches. However, the findings also point to a need for future research that explores practical and scalable tools and techniques to map and evaluate WASH systems, and ways to engage relevant actors in these approaches to collectively apply systems knowledge.