The Taipei Water Source Domain is the major water source of the Greater Taipei Area. With the water from the Nan-Shin and Bei-shi watersheds, this area is a water source for the five million people in Taipei. In order to manage and maintain the Nan-Shin watershed in the Taipei Water Source Domain and protect the valuable local resources, in this study we look at the management of Nan-Shin watershed and examine ways to reinforce the local communities, social resources, and public participation. After reviewing past literatures and conducting in-depth interviews with the local stakeholders, the issues identified are: (1) scattered jurisdiction and conflicts between regulations, (2) limited land use and development posing problems for the local residents, (3) water-source and ecological issues caused by hot-spring tourism, and (4) insufficient base-flow in the downstream of Nan-Shin River. In order to solve these problems, in this study the policy network theory for cross-domain management was utilized, and the perspectives of interdependent governance and policy enforcement were incorporated into an overall design of governance and a public-private collaboration mechanism for watershed management. By understanding the current status and utilizing the bottom-to-top perspective, the in-depth interviews with the local stakeholders helped clarify the core issues, and critical factors and strategic consensus were identified using the Analytic Network Process (ANP). The humanistic, quantitative interviews combined with scientific, systematic analysis helped clarify the key issues and influential factors in the areas of interest, and solutions agreeable to the stakeholders were also determined. It was discovered that most of the stakeholders believed the best way to change the current status in the management of Nan-Shin watershed was to “establish a cross-departmental, dedicated committee.” In other words, the Taipei Water Source Domain requires a dedicated decision-making platform that enforces the policies before a balance can be reached between the society, economy, and ecology. Only by doing so can sustainable management be achieved and a high-quality watershed management strategy takes place. In addition, by making reference to cases in Taiwan and other countries and conducting follow-up, in-depth interviews, it has been made clear that the current governmental agency managing the Taipei Water Source Domain is lacking in the capacity of negotiating and getting straight to the point, and the local social-capital structure also has room for improvements. It is suggested by this study that an improved governmental capacity fully enforcing the policies will help congregate the local social capital and in turn achieve interdependent governance between the national and society. Lastly, the following suggestions were proposed regarding the future directions of the management of the Taipei Water Source Domain. 1. Improve and increase inter-agency communication and collaborations through the existing managerial agencies. 2. Establish a cross-departmental committee or watershed agency that is in full charge of the relevant tasks. 3. Develop a strategic map of the area's governance and step by step achieve high-quality governance of the entire area.