The large open reservoirs of Umm el Jimal are among the most visible features of the site — deep stone-lined basins that could hold tens of thousands of litres of water collected from the surrounding dams and channels. Several of these reservoirs survive intact, their basalt walls still waterproof after more than a millennium of disuse.
Within individual buildings, smaller cisterns were cut directly into the rock floor or built into corners of rooms. The regularity with which they appear — in what were clearly ordinary domestic spaces — illustrates how central water storage was to life in this town. The cisterns were private infrastructure, built and maintained by individual households, alongside the communal reservoirs that served the whole community.