Safely Managed On-Site Sanitation: A National Assessment of Sanitation Services and Potential Fecal Exposure in Indonesia

Abstract

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.

Keywords: Indonesia; fecal exposure; inequalities; on-site sanitation; safely managed services; sustainable development goals.

Figure 1

Household sanitation facilities use and emptying across four population density categories at municipality and district level (over 10,000 people/km²: n = 14, 1000–10,000 people/km²: n = 94, 100–1000 people/km²: n = 189, <100 people/km²: n = 217). Note that, given local contexts and best available data, septic tank age and emptying practice over the last 5 years were used to differentiate between ‘contained’ and ‘uncontained’ septic tanks. The item ‘septic tanks equal to or over 5 years old (not emptied)’ includes the item ‘septic tank age unknown (not emptied)’ and was used as a proxy for ‘uncontained’ septic tanks.

Figure 2

Proportion of households using septic tanks that were emptied (a) (top left), practicing open defecation (b) (bottom left), and using sanitation facilities that directly discharge human waste to environment (c) (top right) by population density. Each dot represents one municipality (grey circle, n = 99) or district (black circle, n = 415).

Figure 3

Proportion of households reporting septic tank emptying over proportion of villages experiencing flooding (a) (left) and proportion of villages experiencing drought (b) (right). Each dot represents one municipality (grey circle, n = 99) or district (black circle, n = 415).

Figure 4

Average population density of open defecation, direct discharge of human waste into environment from sanitation facilities, and septic tanks over 5 years old that were not emptied (a proxy for ‘uncontained’ septic tanks), respectively, over population density categories of municipalities and districts (over 10,000 people/km²: n = 14, 1000–10,000 people/km²: n = 94, 100–1000 people/km²: n = 189, <100 people/km²: n = 217). Error bar represents 95% confidence interval of the mean.

Figure 5

Inequalities in the proportion of households with potential fecal exposure pathways including (a) open defecation, (b) use of a sanitation facility that discharges human waste directly into the environment without treatment, (c) use of a septic tank that was not emptied, (d) use of a septic tank that is over 5 years old and was not emptied (‘uncontained’ septic tank), (e) use of groundwater for drinking, and (f) use of groundwater for drinking with a septic tank within 10 m from the water source. Note that, for (c), the denominator was the number of households using a septic tank, while for (d), it was the number of households using a septic tank that is over 5 years old. Square, circle, and triangle denote “richest”, “average”, and “poorest” quintiles, respectively. The scale of all six figures (a–f) is the same despite different ranges.