Dates (Phoenix dactylifera L.) are important for heritage, cultural, religious, and economic reasons in the Middle East, South Asia and North Africa. These regions are arid and hyper-arid and so the date palm-trees need to be irrigated. Traditionally, date palms were sustainably irrigated using groundwater resources. Since ancient times, in the United Arab Emirates (UAE) and across the Arabian Peninsula, so-called aflaj systems were used to supply water to irrigate the palms, inter alia. These aflaj systems drained groundwater from higher elevations under gravity through man-made tunnels eventually bringing the groundwater to the surface. From this now-surface source, water was then distributed through channels for irrigation, plus it was also used for household and religious purposes (http://whc.unesco.org/ en/list/1207/). In classical Arabic, aflaj (the singular is falaj) means to ‘split into parts’. Dates were traditionally grown in surface irrigated basins in which there was usually also a cover crop that could grow under the canopy of the date palms. Groundwater remains the prime source of irrigation water in the regions, but due to increased demands for irrigation, and via modern pumping systems, it is under threat from declining quantity and rising salinity. Usage of groundwater now well exceeds the rate of natural replenishment in this hyper-arid region. While there are merits in seeking to improve the efficiencies of modern irrigation systems, regulatory solutions need to be found to protect the natural capital stocks of groundwater. Of fundamental importance is the need to determine the actual water requirements of date palms under these hyper-arid conditions. Here we review our work in the hyper-arid UAE on developing sustainable rates of irrigation that can be used for regulatory purposes. We also highlight the benefits that can accrue from using solar-power desalinated water to irrigate palm trees, as well as detailing the concerns that would ensue from the disposal of the reject brine from these desalination units.