Irsyan Hasyim, Jakarta – A study by the Research Center for Environmental Studies (PPLH) at IPB University's International Research Institute for Climate Change has shown that most of Jakarta's rivers, lakes, reservoirs, and groundwater are heavily contaminated.
Summarizing the results of monitoring research on the water quality in Jakarta in 2025, Deputy Head of the Jakarta Environmental Agency, Dudi Gardesi Asikin, stated that the parameters of river and reservoir water do not meet the standards. These parameters include phenol, total phosphate, total nitrogen, biological oxygen demand (BOD), E. coli, and fecal coliform bacteria.
One cause of this condition is gray water, which is wastewater from baths, showers, sink drains, and washing machines that does not contain feces or urine. This waste is not well managed. "This is followed by people's behavior in disposing of waste and the waste management systems by micro, small, and medium enterprises and settlements, which are not well managed," said Dudi in a written statement on Wednesday, December 10, 2025.
The Executive Secretary of PPLH IPB University, Liyantono, divided the rivers in Jakarta into six clusters to prioritize management. This classification is based on the typology and pollution level of each river section. The characteristics of the rivers are adjusted based on several criteria, including width, depth, meandering, and flow velocity in the observed sections of the rivers. The results will be calculated with pollution index values measured at specific points along the river.
"For example, the correlation found in the Kali Cideng River section is predominantly heavily polluted," said Liyantono. "This matches the conditions of the water, which has slow flow and receives input only from grey water channels from residents."
Another finding, according to Liyantono, is that people's behavior towards domestic waste management and sanitation is relatively similar. People's behavior and awareness have a greater influence on pollution problems. Septic tanks that do not meet standards can also lead to seepage into the groundwater, causing pollution.
The Faculty of Engineering's Institute of Technology at the University of Indonesia also found fecal coliform bacteria in residents' groundwater. "In accordance with Minister of Health Regulation No. 2 of 2023, there shouldn't be any fecal coliform bacteria in groundwater at all," said Liyantono.
There were also findings regarding the practice of open defecation in lake and reservoir areas in Jakarta. IPB University researcher Zaenal Abidin cited the conditions at the Rawa Kepa Reservoir, where gray and black water from household piping systems flow directly into the reservoir. This situation increases the risk of fecal coliform and fecal coliform bacteria entering the water.
"Communal septic tanks and waste management systems should be widely implemented to improve environmental quality," said Zaenal.