WaterAid country programmes increasingly use mapping as a tool to support their ongoing work in-country. Mapping is used as an advocacy tool as a way of providing citizens and local governments with information and arguments to demand improved services and, on an operational level, to improve the sustainability and equity of service delivery. Although mapping is still in a pilot phase in many countries, it has already gained considerable popularity across different country programmes. The objective of the WaterAid learning for advocacy and good practice: water and sanitation mapping project is to support learning around these emerging practices by documenting different approaches and by identifying factors that inhibit or facilitate the uptake of mapping information in policy processes. This is one of a number of case studies, looking specifically at the experiences of mapping in Malawi and Tanzania.