Globally, climate change is triggering shifts in water availability, especially across arid and desert landscapes similar to that in Yemen, where precipitation patterns are increasingly erratic. Here, we use water budget calculations, drought metrics, and trend analyses to examine climatic water deficits, with the aim of unraveling irrigation demands and overall water stress across Yemen. The results indicate that 94% of the influx is lost back to the atmosphere via evapotranspiration, 6% is converted to runoff, and only a negligible amount, generally less than 1%, is retained as storage. The results also show an unrelenting, statistically significant water deficit increase of 0.17 mm yr−1 on the Sen’s slope, at the critical Z-value of 0.005 across the country, for the past 63 years. Our findings challenge the conventional understanding of water deficits across Yemen and suggest that the country’s water resources situation is direr than was earlier documented. Further results show that while the water shortage mosaic across the country experiences interannual variations, their occurrence is significantly intensifying. As such, an immediate and radical modernization of integrated water management systems, including concerted investments in irrigation and artificial recharge wells, especially across the Arabian Sea Coast, the Red Sea Coast, and the Highlands, is strongly recommended.