In ancient Hellas, water management began in the early Minoan Era (ca.
3200–1100 BC) and was related to the geomorphology, the geology, the topography, and the local climatic, hydrological, and socio-political conditions. Historical and archaeological evidences show that ancient Greeks had developed even qanat-related technologies since the Classical times. During democratic periods, the focus of water management was on sustainable small scale, safe, and cost effective management practices, and institutional arrangements, whereas in oligarchic periods, emphasis was on the construction of large-scale hydraulic projects, including aqueducts and/or qanats, mostly related to the public sectors. Aqueducts-like qanats are gently sloping, artificially constructed underground galleries, which bring groundwater from the mountainous area to the lowlands, where water is used, sometimes several kilometers away. It is worth noticing that no large-scale lifting techniques were available, and water was transferred from the source (usually a spring) by aqueducts (qanats) from a higher elevation to a lower level by gravity. Historically, the aqueduct-like qanat technology was developed by Persians in the middle of 1st Millennium BC, and spread towards the Arabian Peninsula and Egypt. The expansion of Islam led to diffusion of qanats in Mediterranean countries (e.g., Spain, Italy, and Cyprus). Much of the population of Iran and other arid countries in North Africa and in Asia depend on water supply by aqueducts-like qanats, even today. This technology is characterized by its durability and sustainability, although an aqueduct-like qanat is expensive, both in construction and maintenance. It is pointed out that, the technique of tunneling was used during the Classical period in ancient Hellas. Since the well known tunnel at the island of Samos, Hellas, was designed and constructed by Eupalinos (ca.
530 BC), several underground tunnels (with and without well-like vertical shafts) in order to convey water from one location to another one located in a lower level were implemented in this country. Several aqueducts (qanat) paradigms (e.g., in Athens, on islands of Crete and Rhodes, and in the area of Serres in north country), which are in use even today, are presented and discussed. Overall, it seems that water-related problems of modern societies are not very different from those during antiquity.