Sekadau, Indonesia – Children's laughter skimmed over water the color of mud as mothers wrung laundry over banks where the Sekadau joins the Kapuas, the longest river in Indonesia.
Local testimony along the Kapuas River, which flows 1,143 kilometers (710 miles) east to west from Borneo's M ller Mountains out into the Natuna Sea, suggests this river – like many flowing across the world's largest archipelagic country – may be losing prominence as a center of community life.
"The river is dirtier now and no longer a gathering place like before," an older resident told researchers from Tanjungpura University downriver in Pontianak, the capital of West Kalimantan province, for a study published in September.
But here in Sekadau, the river remains central to daily life – a place to bathe, wash vegetables, and, until recently, to defecate.
Research conducted on the Kapuas from 2020-2022 and published in the Journal of Aquaculture and Fish Health last year recorded double the legal limit of lead, a heavy metal pollutant that impairs neurological development – and 24 times the maximum coliform bacteria level for rivers permitted by Indonesia's government.
The study authors said the dangerous coliform level reflected the rapid population growth that has taken place in recent decades along the banks of the Kapuas. Some here in the village of Sekadau, the seat of an eponymous district on the Kapuas, say they hope the hardening of Borneo's main arterial river can still be mended.
From 2002-2024 West Kalimantan province lost one-fifth of its old-growth rainforest, according to Global Forest Watch, a satellite imagery platform managed by the World Resources Institute, as plantation and mining activities expanded over the landscape.
A comprehensive cleanup of the Kapuas would likely require cracking down on the mines and other industrial operations polluting the water, researchers say, on a scale similar to government drives to rehabilitate major rivers in Java like the Citarum.
However, some behavioral shifts taking place here along Indonesia's longest river appear more positive, with local authorities on this confluence reporting an important environmental and public health milestone this year.
Flow state
Absence of toilets spawns a grim whirlpool of health and development problems – from gut-wrecking parasites, which bring chronic conditions and anemia, to life-threatening acute bacterial infections like E. coli and typhoid.
"This pollution has the potential to spread bacteria that cause gastrointestinal infections, including diarrhea and gastroenteritis," said Prasetyo Widhi Buwono from Indonesia's association of internist doctors.
Research long ago upheld links between open defecation and child stunting, which increases the probability of cognitive impairment and negative health outcomes long into adulthood.
A 2020 study in India established a 14% increased likelihood of stunting among children whose parents still lacked access to toilets.
In 1999, the government of India under Prime Minister Atal Bihari Vajpayee launched the Total Sanitation Campaign, pumping direct financial assistance to households to build toilets for the first time. The proportion of residents inhabiting India's vast rural areas practicing open defecation then fell from 85% in 2002 to 17% in 2022, among the most consequential shifts in public health ever recorded.
Continued progress elsewhere may prove challenging as populist governments in some wealthy countries pull back aid commitments to low- and middle-income countries.
The dismantling of USAID, the United States' foreign aid agency, by the Trump administration abruptly canceled hundreds of millions of dollars of sanitation and water projects around the world. USAID provided $55 million for water supply, sanitation and hygiene projects in Indonesia from 2012-2014, for example.
Henry Alpius, who leads the family planning and health office at Sekadau district, said open defecation in the district was linked with higher instances of diarrhea, a common scourge accounting for around 10% of deaths among children under the age of 5, according to UNICEF, the United Nations' children's agency.
Indonesia's statistics agency, the BPS, noted that more than one in five households in Sekadau lacked their own toilet in 2021, a fact residents here in the interior of Borneo attributed to either cost or space – or, in the case of 28-year-old Rita, both.
"My house is small, there's no space to build a toilet," Rita told Mongabay Indonesia.
"If you want to build a toilet, you need a lot of money," she added. "Toilets are expensive, and there are times you barely have enough just to meet your daily needs."
Others here in Sekadau said they had invested in the infrastructure only for heavy rains to overwhelm septic tanks, unleashing foul and dangerous overflow over residential space.
Ningsih, a resident who lives on the riverbank, installed two septic tanks only for both to break due to the challenges of poor weather and awkward topography.
"The water entered the septic tank and it eventually failed," Ningsih said. "So we were forced to return to the river."
Yet in August this year, following collaboration by civil society and community with local government support, the Sekadau government declared that the district of 211,559 people was free of open defecation.
Straight flush
Indonesia's more than 84,000 village governments are obligated to allocate 20% of their budget for health care, a requirement that has supported the five objectives of Indonesia's sanitation program, known as STBM, said Henry, the Sekadau health lead.
"[Local government clinics] have to play an optimal role in collaboration with village and district governments," Henry added.
In Sekadau, fieldworkers from the nonprofit Wahana Visi Indonesia, the local affiliate of Christian charity World Vision International, have also worked with local government and the community on sealed anaerobic alternatives to septic tanks, adapting a design by three young people in Sekadau: M. Indra Kusuma, M. Rifani and Rusdiani.
The design, known as Gentong Mas Santun, is better suited to local riverbanks, explained Margaretta Siregar, the nonprofit's regional manager.
"Gentong Mas Santun is an alternative solution for residents who struggle to build septic tanks due to topographical conditions," Margaretta said. "With this innovation, more families can have access to healthy toilets."
Twice a week, Ningsih now dissolves a dash of chlorine into the Gentong Mas Santun unit. Adding a homespun solution of effective microorganisms, commonly known as EM4, speeds up anaerobic digestion, removing much of the bacterial threat from untreated wastewater. The system brings significant harm reduction, though it isn't a perfect environmental solution.
"You can make your own EM4 solution by mixing water and sugar, then fermenting it until it's ready to use," Ningsih said.
Interviewees said the Gentong Mas Santun system cost around 2 million rupiah ($120), much less than the 3 million to 5 million rupiah ($180-$300) needed to buy and install a septic tank.
Rita described the meaningful change this has brought to her family life. For one, she no longer worries about her children going to the river.
"It's more practical because we have our own toilet," Rita said.
Wahana Visi Indonesia has overseen installation of 28 of these Gentong Mas Santun toilets along the riverbanks, working together with the community in Sekadau.
Eliminating open defecation is one of five strands of the overall sanitation program, alongside handwashing, managing household drinking water and food safety, waste management, and wastewater treatment.
Ningsih said she no longer worries during storms, thanks to the improved durability of the Gentong Mas Santun. Data from the Sekadau clinic show the changes taking place are improving lives here on the river.
In 2015, local authorities recorded 3,192 cases of diarrhea in Sekadau, which declined to 581 incidences last year, a reduction of more than 80%.
The district regulated in 2017 to implement the national sanitation program, when as many as half of people in Sekadau used to throw wastewater into the river, according to district leader Aron.
And this year the elected head of the district announced open defecation was no longer practiced in any of Sekadau's 94 villages.
"Sekadau district has now successfully achieved its target of being open defecation-free," Aron said at his office in September.
World Health Organization data showed that the population practicing open defecation in Indonesia's rural areas declined from 19% in 2015 to 7% in 2022.
Until recently, some young children in Sekadau would have to walk carefully under torchlight to a public over-water latrine.
"Generally, people who have been practicing open defecation for a long time find it difficult to change their habits," said Margaretta from Wahana Visi Indonesia. "But that doesn't mean it's impossible."
Citations
Ihsan, T., Tanjung, P., Honey, E., Amanda, M., Putri, D., & Hafizi, M. Z. (2025). The role of the Kapuas River in shaping social interaction and cultural acculturation in multicultural communities. JUPSI: Jurnal Pendidikan Sosial Indonesia, 3(2), 58-65. doi:10.62238/jupsi.v3i2.179
Rahayu, W., & Sari, D. W. (2023). Health risk assessment via the consumption of clam (Corbicula largillierti) accumulated heavy metals (Pb) and coliform bacteria at Kapuas River, West Borneo. Journal of Aquaculture and Fish Health, 12(2), 281-288. doi:10.20473/jafh.v12i2.22985