The participatory approach for Davao city is evaluated through access to information on a local level, and meaningful opportunities for engagement. Management as a successful process requires criteria that are specific and unique to the grassroots framework, where participants and users are included in the collection, dissemination, and benefits of the knowledge and data, that is the co-generation of knowledge in a practiced, politically recognized, on-the ground reality. The holistic picture of water balances of the watershed constructed in this study is a useful interpretation on the basis of best efforts constructed from the existing statistics, to discuss secure use of water in a sustainable manner. To demonstrate the use of water balance, pollution from point and non-point sources within the watershed are discussed using Total Maximum Daily Load. The estimated inputs to model availability and contamination are outlined within this research to act as suggestions for open-source community based monitoring efforts. From the process-based research, the localized data does not have rigorous, representative data sets which account for appropriate management-level modeling.