The relevance of the main instruments of international water law to the hydraulic development projects of later-developing upstream states is explored, for a non-legal audience. Relevance is gauged by querying common misperceptions, checking the compatibility of the instruments, and considering their effect along the Nile, Jordan and Tigris Rivers and associated aquifers. Specific principles of international water law are found to support upstream development in theory, though its relevance is threatened by incompatibility of clauses between the instruments, the erosion of norm-building processes, and a shift away from the idea that territorial sovereignty over a fluid resource should be limited.