This paper seeks to demonstrate the potential role of the Public Trust Doctrine (PTD) in the management, restoration, and protection of water resources, as well as its power as one of the most useful case law doctrines in the U.S. legal system. The focus of my research is on the Hawai'i Supreme Court decision regarding distribution rights for the water transported by the Waiahole Ditch irrigation system. The research will seek to establish, by using the 2000 Supreme Court ruling as a case study, the role the public trust doctrine can play as a legal tool in communities regaining and protecting their local water resources. The method of research is a qualitative case study using documents, reports, court papers, and interviews. The findings from my research suggest that, as a part of U.S. common law, the public trust doctrine plays an important role in both the framing of policy and the legal decision-making process, but that the doctrine cannot stand alone as a positive law or policy to necessarily guide decisions in the protection and management of water resources. The research further shows that there are numerous factors to consider when framing a legal argument to protect water resources, but that public trust principles can play a critical role in any such discussion. The public trust doctrine also provides a framework for the discussion of various issues included in the decision-making process, including the broader public education, environmental considerations, and the social and cultural aspects of policies and legal decisions.