Water Pollution of Some Major Rivers in Indonesia: The Status, Institution, Regulation, and Recommendation for Its Mitigation

River water pollution is a significant environmental problem in Indonesia. On the other hand, river water is an important source of drinking water. Therefore, clean and safe water has become a priority program of the Government and is parallel with the international agreement known as the Sustainable Development Goals (SDGs). Rapid population growth and industrialization cause inadequate access to safe water; only 73 of Indonesian people can access safe water. This review paper aims to present a comprehensive discussion concerning water pollution in four big rivers, i.e., Siak, Citarum, Bengawan Solo, and Brantas Rivers, that have experienced pollution and provide alternative solutions to mitigate the pollution. Data were collected from related institutions, governments’ regulations, the authors’ experiences, and literature studies. Developing a riparian zone with multiple ecological services and introducing Internet of Things (IoT) devices that monitor and provide real-time water quality information is essential for mitigating river water pollution. Law enforcement is an alternative method to reduce point-source pollutants from industries. Non-point source pollutants from domestic and agricultural wastes may be reduced through spreading awareness and implementing personal and environmental hygiene, involving the community in designing, as well as monitoring and evaluating water quality. Those approaches should be accompanied by proper institutions, regulations, and policies.