Effective groundwater management requires that decision makers choose strategies for the allocation and conservation of water resources that satisfy the objectives of, and draw support from, multiple stakeholders with complex and often contradictory value judgments. We demonstrate a value of information (VOI) approach to assess the benefits of acquiring geophysical data as part of a groundwater management strategy in light of data uncertainty. VOI is a method for determining if the acquisition of information improves a decision maker’s ability to select an optimal action given value judgments, risk tolerance, and anticipated consequences of the action. As a practical example we examine the uncertainty associated with time-domain electromagnetic (TDEM) data and evaluate the contribution of these data to management of desalination operations in a coastal aquifer where there is a risk of contaminating freshwater resources. The reliability of TDEM data is evaluated using a forward modeling approach to calculate data sensitivity to parameters of interest in the decision analysis. We evaluate the value added by acquiring uncertain data using a standard VOI approach. The analysis shows additional geophysical information could improve groundwater managers’ ability to make decisions about desalination operations and quantifies the contribution of geophysical data to the management decision. We note several measures that can be taken to improve estimates of the data reliability as well as the valuation of alternative actions.