Reliable water availability is critical to sustaining community water supplies and determining economic development opportunities. In many cases, particularly in remote and arid areas such as in the Anangu Pitjantjatjara Yankunytjatjara (APY) Lands in the far northwest of South Australia, groundwater is the only viable source of water. The Goyder Institute for Water Research’s Facilitating Long-term Outback Water Solutions (G-FLOWS) suite of research projects has developed new techniques to interpret airborne electromagnetic (AEM) geophysical data, coupled with hydrogeological techniques, to identify groundwater resources buried by deep sedimentary cover. The Stage 3 work program aimed to validate the AEM geophysical interpretation by establishing hydrogeological control sites as a part of a drilling program. Drilling revealed a new fresh groundwater resource (<1,000 mg/L) in the Lindsay East Palaeovalley which has enormous potential for the future development of the APY Lands. Additional hydrogeological investigations are needed to determine the size and sustainability of this groundwater resource. This article focuses on the hydrogeological aspects of the drilling program.