This case study discusses the implications of imposing the doctrine of public trust to ground and surface waters within the State of Hawaii and its effects on traditional rights that had previously evolved based on common law. It traces the major events of the history of water rights and practices beginning with the system devised by the indigenous Hawaiian people prior to the adoption of the doctrine of public trust to the water resources of the State of Hawaii, applied with the most expansive interpretation of the public trust doctrine, encompassing both surface and subsurface waters and a wide assortment of protected uses and purposes. The major decisions that ensued when applying the doctrine, via legal prescriptions and administrative rules, are described. The implications of the interplay between scientific enquiry and research are presented, with legal precedent in the face of potential water shortages, competing uses, sensitivities to comprehensive resource management, considerations of ecological balance and protection of the rights of indigenous people. Many of these findings are transferable to other jurisdictions contemplating the adoption of public trust doctrine principles to their surface and ground waters.