Access to safe sanitation and the elimination of open defecation are pre-conditions for improved child health and nutrition and wider achievement of the Sustainable Development Goals (SDGs). While Indonesia has a solid policy framework, the country ranks third globally in terms of numbers of people practicing open defecation. Our aim was to assess the effectiveness of a five-year strategy to reduce open defecation through accelerating implementation of the national sanitation program across districts receiving variable levels of external support. Among three provinces with poor sanitation program performance, districts were selected to receive one of three levels of external support. High intensity districts (n = 6) benefitted from enabling environment strengthening support including political and social mobilization, direct capacity development, and efforts to strengthen planning, budgeting, monitoring and supervision; learning districts (n = 16) benefitted from cross-district learning opportunities and political mobilization through provincial government advocacy efforts; and comparison districts (n = 58) were monitored under routine program conditions. Outcomes included open defecation free (ODF) status and new toilet facility construction and were assessed through village level monitoring systems across all districts. Negative binomial regression and multivariate analysis were used to assess associations between levels of intervention intensity and outcomes. Among districts receiving high-intensity external support improvements in political commitment, planning, coordination, financing, monitoring and supervision were observed. Relative to comparison districts, high intensity districts were more likely to be ODF (aRR 4.65, CI 2.12–10.20) with greater increase in household toilet coverage (aRR 11.15 CI 1.04–119.82). Weaker non-significant associations with ODF were observed among learning districts relative to comparison districts. Efforts to strengthen provincial and district government capacity to implement sanitation programming in Indonesia can yield substantial improvements in outcomes in a relatively short period of time.

Sustainable Development Goal target 6.2 calls for universal access to adequate and equitable sanitation, setting a more ambitious standard for ‘safely managed sanitation services’. On-site sanitation systems (e.g., septic tanks) are widely used in low- and middle-income countries (LMICs). However, the lack of indicators for assessing fecal exposure risks presents a barrier to monitoring safely managed services. Furthermore, geographic diversity and frequency of disasters require a more nuanced approach to risk-informed decision-making. Taking Indonesia as an example, the purpose of this paper is to provide insights into current status and practices for on-site sanitation services in the contexts of LMICs. Using a dataset from a national socio-economic survey (n = 295,155) coupled with village census (n = 83,931), we assessed (1) household sanitation practices across Indonesia stratified by city-level population density and meteorological factors, (2) factors associated with septic tank emptying practice, and (3) inequalities in potential fecal exposure as measured by population density and WASH access by wealth quintile. We found a high reliance on on-site sanitation facilities (80.0%), almost half of which are assumed to be ‘uncontained’ septic tanks and one in ten facilities discharging untreated waste directly into the environment. The most densely populated areas had the highest rates of septic tank emptying, though emptying rates were just 17.0%, while in the lowest population density group, emptying was rarely reported. Multivariate regression analysis demonstrated an association between flooding and drought occurrence and septic tank emptying practice. Higher groundwater usage for drinking among poorer households suggests unsafe sanitation may disproportionally affect the poor. Our study underscores the urgent need to strengthen the monitoring of on-site sanitation in LMICs by developing contextualized standards. Furthermore, the inequalities in potential fecal exposure require greater attention and tailored support mechanisms to ensure the poorest gain access to safely managed sanitation services.