Nexus data must facilitate stakeholder and analyst understanding of nexus scope, locations, production, consumption, diversion, return flows, and conveyance possibilities along with costs. There is important need for data that supports efforts to understand system boundaries, and spatial dimensions, along with the origin and fate of WEF commodities plus cross-sector interactions and interfaces. A wide, rather comprehensive set of data are necessary across the full WEF scope as the nexus approach is about widening perspectives to unexplored levels. Additionally, WEF nexus data systems need to reflect study region uniqueness incorporating appropriate activities with contents varying as focus shifts from place to place. Challenges arise in representing appropriate scope, mix of enterprises, stochastic variation in water supplies, WEF commodity production practices, WEF commodity market prices, and costs and returns from ongoing and potential future technological choices. Data challenges arise due to proprietary interests, scale differences in analysis, model requirements, representation of unexplored possibilities, assembly cost, projections of the future, representation of stochastic variation, quick query and retrieval systems, and integration with visualization. Comprehensive, innovative procedures are needed for data collection, storage/retrieval and inference in support of high quality WEF nexus analyses.