Introduction: This research studies the severe case of water resource conflicts at the Surakarta Ex-Residency, Indonesia. The researchers were interested in studying this case as they wanted to provide a solution to the water resource conflicts that happened at the Surakarta Ex-Residency through an eco-region-based environmental policy principle. This research aims: (1) To describe the water resource conflicts at the Surakarta ex-Residency, Central Java, Indonesia, (2) To identify the governmental policies on water resource management that cause water resource conflicts, and (3) To formulate ecoregion-based water resource management policy model to resolve water resource conflicts. Methods: This was socio-legal research with doctrinal and non-doctrinal approaches. Results: The research results show that the water resource conflicts between the society and the Municipal Waterworks that have control over the water resources happened due to policies that allowed water management for commercial interests. Conflicts also happened between Regional Governments, as a result of an inaccurate understanding of regional autonomy. This leads to the formulation of water resource management policies that are merely based on regional egos. Discussion: The Regional Government's policies on water resource management contribute to the emergence of water resource conflicts. This is because such policies are directed to various orientation forms, namely economic orientation, privatization, and the unsynchronized water resource management regulations between Regional Governments. The water resource conflict resolution policy with the ecoregional approach is carried out through a mutual agreement between Regional Governments, that will be followed up by each of those Regional Governments. Conclusion: The legitimization is in the form of Regional Regulations that regulate the imposition of responsibilities as well as the rights on the water resource management.