In this project, we inventoried and assessed the stocks and flows of freshwater in Hawai‘i’s natural systems and human economy, following the integrated approach proposed by the United Nations’ System of Environmental-Economic Accounts for Water. In partnership with potential users of this information and providers of the data, as well as national and international experts, we developed reporting protocols and accounting tables for the Hawaiian Islands that are consistent with national level methods. They include (1) compiling integrated hydrological-economic water supply and use, and asset accounts; (2) identifying data gaps and next steps; and (3) raising awareness of accounting as a tool for sustainable management. The resulting island-scale water supply, use tables, and asset accounts detail stocks and flows between the environment and the economy for the two islands (O‘ahu and Maui). The products can serve as a clarifying guide to make fundamental choices about Hawai‘i’s various paths to economic development. The research can directly inform difficult choices about the water-energy-food nexus critical to Hawai‘i’s sustainability and security.