Excavations at the Bronze Age seaport on Pseira Island uncovered the remains of sophisticated water retention systems that included the addition of retaining walls to prevent erosion, massive dams with associated reservoirs, and small check-dams to ravines that reached over one hundred meters in length in order to control water runoff and make it available for human use. Agriculture was one of the cornerstones of the Bronze Age Cretan economy, and it is no surprise that the ancient inhabitants of the island went to great lengths to control water runoff and make it available for human use. Despite the application of traditional archaeological survey methods, the full extent of the water management systems was not understood fully as the island’s rugged topography prevented intensive and thorough survey of many places. The use of a differential Global Positioning System (dGPS) unit provided the opportunity to take a fresh look at the evidence for water management on the island. The results of this study contribute substantial amounts of new information on the little known subject of Minoan water conservation and control.