The ancient Qanat system, which originated in Iran around 800 BC, is a unique methodology to irrigate arid and semi-arid regions. Qanats have contributed to forming civilizations under these harsh conditions. Underground tunnels following an aquifer collect water from different layers of earth by relying only on gravity alone. The Qanats minimize evaporation loss and ensure an efficient use of the available water resources. Qanats are owned communally; the Qanat water, which is of high quality, is distributed on a rotational basis. Construction and maintenance of Qanats requires skilful workers and cooperation among the community members. Farmers select diverse crops that complement each other in terms of water requirement. In order to preserve these benefits it is necessary to maintain the ancient Qanat irrigation systems including their agro-biodiversity on a sustainable basis.