Reviews of the historiography of irrigation regularly single out Karl August Wittfogel’s “hydraulic hypothesis” as a uniquely deleterious contribution to the study of ancient water management. His errors notwithstanding, this article argues that the ideological misshaping of Western scholarship on irrigation instead emerged from Egypt’s long colonial experience. First articulated in the Napoleonic Description de l’Égypte, the theory of a centralized, ancient Egyptian “hydraulic state” was crafted to justify French attempts to reshape Egypt’s irrigated landscape. British hydraulic engineers later received and refined this narrative during the British colonial period. Their popularizing discourse retrojected the technocratic character of modern irrigation into antiquity, defining the Egyptian “irrigation system” as a static and unchanging fusion of hydraulic expertise and state power. Widely disseminated in specialist and popular fora, this tendentious argument had become received wisdom by the beginning of the twentieth century and subtly shaped early Egyptological descriptions of irrigation in antiquity.