I have been living in Indonesia for a while now as a PhD student in environmental science, and one thing that keeps coming back to me is a kind of gap I did not expect to find.
People here, at least in the places I have been, take personal cleanliness seriously.
Handwashing before meals, tidying up around the house, keeping things neat — that is just normal.
But the infrastructure side of sanitation, the pipes, the treatment systems, what actually happens to waste after it leaves the house, that is a different story.
And the more I learn about it through my studies, the more I notice it in everyday life.
To be fair, Indonesia has made real progress and I do not think that gets said enough.
The national program called STBM, which stands for Community-Based Total Sanitation, has pushed open defecation down from around 32 million people in 2015 to roughly 2 million by 2024 (The Water Diplomat, 2026).
That is not a small thing. Septic tank coverage has also expanded a lot over that same period, which makes sense for a country this large and spread out — you are not going to run centralized sewer pipes to every village on thousands of islands.
The community-scale approach was probably the only realistic one.
But here is what the numbers do not always show. Having a septic tank and having a functioning septic tank are two different things.
Studies have found that around 83% of septic tanks in Indonesia do not meet basic standards, mostly because they are never emptied or maintained (Widyarani et al., 2022).
The waste has to go somewhere, and often it leaks into the soil or nearby groundwater — the same groundwater that households use.
In parts of the Upper Citarum River, domestic wastewater accounts for the majority of organic pollution.
It is one of those problems that is easy to miss because it is slow and invisible, unlike a pile of garbage on the street.
Plastic makes everything more complicated. Indonesia generates close to 7.8 million tonnes of plastic waste every year, and a large portion of it ends up burned, dumped, or carried into waterways (World Bank, 2021).
Four Indonesian rivers are among the worst in the world for plastic flowing into the ocean, and microplastics have already shown up in fish sold in Jakarta markets (Iacovidou et al., 2025).
Sanitation and solid waste are technically different sectors but they share the same rivers and drains, so the problems end up mixed together.
There are also consequences of poor sanitation that rarely come up in public discussions.
Untreated wastewater releases methane and nitrous oxide, both of which are far more potent greenhouse gases than carbon dioxide, which means sanitation is actually a climate issue too.
Then there is antimicrobial resistance — untreated sewage is one of the main ways resistant bacteria spread between people, animals, and the environment, and the WHO has specifically flagged proper wastewater management as part of the response to that problem (WHO, n.d.).
These are not niche concerns. They connect directly to health, climate, and food safety in ways most people do not immediately associate with sanitation.
Something that really stuck with me from one of my classes was a paper by Indrayadi et al. (2023) about a community called the Dayak Bakumpai, who live along the Barito River in South Kalimantan.
The researchers found that people there were not using toilets — not because they did not know the health arguments, but because floating latrines over the river genuinely made more sense for how they live. Water is central to everything they do.
And in their view, waste that flows away immediately is cleaner than waste that sits in an enclosed pit. The government did try to offer an alternative system, but it was rejected because it did not fit their daily routines or their sense of what proper sanitation actually looks like.
That paper changed how I think about the open defecation numbers, because it showed that the problem is not always awareness or infrastructure — sometimes it is that the infrastructure being offered does not match the lives people are actually living.
The financing gap is also real. Indonesia’s own development plan put the sanitation investment needed through 2024 at around US$11.2 billion, and government funding covered maybe a third of that (World Bank, 2024).
Local governments often spend less than 2% of their development budgets on sanitation. Rural areas and lower-income communities are furthest behind, and urbanization keeps adding new demand faster than the systems can keep up.
So what would actually help?
In my opinion, the biggest shift needed is treating maintenance as seriously as construction. Building a toilet or a treatment unit is visible and easy to report. Keeping it working is neither.
Cities like Surakarta and Banjarmasin have started moving toward scheduled desludging rather than leaving it voluntary, and the difference in water quality outcomes has been measurable (The Water Diplomat, 2026).
That model should be the norm, not the exception. Decentralized treatment systems — constructed wetlands, small anaerobic units — also fit Indonesia’s geography better than trying to build centralized sewers everywhere.
Beyond infrastructure, schools seem like the most underused lever here. Children who learn about water, sanitation, and hygiene in a practical way tend to carry those habits home. That is not a new idea but it is one that gets underfunded.
Communities also need to be involved in designing sanitation solutions, not just receiving them — the Bakumpai case is a good example of what happens when that does not happen.
And individuals can do more than people usually credit: how households manage waste, whether they keep drains clear, whether they support or ignore local clean-up efforts, all of that adds up.
Living here has made me realize that sanitation is one of those issues that touches almost everything else — health, climate, food, education, economic mobility — without ever quite becoming anyone’s main priority.
The progress is real and it deserves to be acknowledged. But the gap between having a toilet and having sanitation that actually works and actually protects people is still wide, and it is mostly invisible.
That, maybe more than anything else, is what an environmental science education has trained me to pay attention to.
By Hana Bouguer
(UNS Environmental Engineering Doctoral Program Student)
