This policy brief summarizes the main find-ings of applied sanitation planning research conducted in small town settings between 2015–2017 in Bolivia, Malawi and Nepal. Good planning requires good data – therefore, this brief policy focuses on the crucial step of data collection to inform the situational analysis. The assessment of the initial situation is necessary as a key, first planning step. With "good" data, we mean data that are (i) mean-ingful, (ii) high quality and (iii) timely, i.e., data which allow municipalities and sanitation stakeholders to make informed decisions.