The Visualising Victoria's Groundwater (VVG) web portal federates groundwater data for the State of Victoria, Australia, thus making legacy data, government datasets, research data and community-sourced data and observations visible to the public. The portal is innovative because it was developed outside of the government and offers real-time access to remote authoritative databases by integrating the interoperable web services they each provide. It includes tools for data querying and 3D visualisations that were designed to meet end-user needs and educate the broader community about a normally invisible resource. The social impact of the web portal was measured using multidisciplinary research that employed survey instruments, expert reference groups, and internet analytics to explore the extent to which the web portal has supported decision making by governments, industry, researchers and the community. The research found that single access, multiple data set web portals enhance capacity by providing timely, informed and accurate responses to answer queries and increase productivity by saving time. The provision of multiple datasets from disparate sources within a single portal has changed practices in the Victorian groundwater industry.