This review provides an overview of the application of hydrogeochemistry in mineral exploration by compiling learnings and knowledge from past and present research. It includes guidance on survey design, sampling methodologies, field data collection, analysis, and interpretations. Hydrogeochemistry is a unique tool with the potential to detect and generate anomalies from mineral occurrences that are deeply emplaced or obscured by post-mineral cover. Pathfinder dispersion from mineral deposits commonly produces proximal and distal dispersion patterns; case studies have demonstrated anomalies detectable up to 10 km away from the deposit source. To date, case studies using streams and groundwaters have demonstrated water to be an effective geochemical medium for vectoring sources of copper, gold, diamonds, base metals (Pb and Zn), uranium, and Ni-PGE mineralisation. Significant technological advances in sample analysis (detection limits) and drilling methods (for groundwaters) have dramatically increased the detectable plume associated with mineral deposits and reduced the time and cost of acquiring groundwater samples. Hydrogeochemistry is an effective early-stage greenfield and regional survey mineral exploration assessment tool. As explorers target ever deeper prospects or enter areas of post-mineral cover, hydrogeochemistry should be at the forefront of an explorer's geochemistry toolbox.

Thematic collection: This article is part of the Reviews in Exploration Geochemistry collection available at: https://www.lyellcollection.org/topic/collections/reviews-in-exploration-geochemistry