Dowsing is an ancient practice that uses rods or pendulums to locate groundwater and other subsurface features. Despite its long history and continued use by individuals and municipalities, dowsing relies primarily on intuition rather than controlled experimentation, in contrast with hydrogeology, which developed as a scientific discipline in the 19th century. Field demonstrations of dowsing are often persuasive; however, in regions with suitable climate and geology, groundwater is ubiquitous, making it difficult to define what constitutes a successful “detection” and to rigorously compare dowsing with scientific methods. Dowsers also claim to detect underground drains and pipes, which provides a more suitable framework for statistical testing. Here, we present the final results of a controlled experiment on dowsing, co-designed by a team of scientists and an experienced dowser. The experiment consisted of a grid of 25 cells, in which various objects were buried in selected locations. These included iron or plastic pipes, empty or filled with water, with water types varying between saline, fresh, stagnant, or flowing. Participants were asked to scan the grid using wooden or metal rods and to identify cells where they believed an object was present. A total of 54 participants took part: 27 with intermediate or extensive dowsing experience and 27 novices who received basic training. Some participants repeated the test to assess reproducibility. Results are analyzed according to object type, dowsing instrument, and prior experience.