The date palm water requirements have theoretically been estimated using the Penman-Monteith model. The grass was considered as the reference crop type with a height of 0.12 m. Agro-metrological data from seven regions, which are popular with date palms, were collected. The annual ETc varies from location to another and approximately falls between 1400 and 2000 mm. The annual irrigation water requirements range from 5500 mm, with an irrigation efficiency equal to 40 % and 0.1 ratio of leaching requirement, to 1500 mm for an irrigation efficiency of 90 % and zero leaching requirement. In other words, the annual volumetric palm water requirements per hectare fall between 15 000 m3 and 55 000 m3 depending mostly on location, level of the irrigation management, and quality of the irrigation water