As Toby Jones’s Desert Kingdom: How Oil and Water Forged Modern Saudi Arabia (2010) points out, Saudi power has always been predicated on the state’s ability to master the environment. The two pillars of Saudi geological imperialism have been oil and water. Yet, there is a tendency to forget that despite the initial discovery of oil in 1933, oil revenues did not begin to radically alter the Saudi state’s capacity for rapid development and authoritarian control until the 1960s. During those early decades, the main source of revenue for the Saudi government continued to come from tax revenues generated by the hajj. As both American and British archival sources make clear, the initial aims of geological surveying often had as much to do with the hajj and water security as with petroleum. Thus, investments in water infrastructure were not of secondary importance to oil exploration. The tendency to overlook these early decades also makes it more difficult for us to grasp continuities between the environmental and sanitary development and centralization projects carried out by the Ottoman Empire in the Hijaz and those of the early Saudi state. Up till now, scholarship on the late Ottoman Hijaz has focused on Pan-Islam, the Hijaz Railway, and the inter-imperial debates surrounding cholera and quarantine. In Ottoman documents, however, the su meselesi or “water issue” often occupied as much or more attention. The ‘Ayn Zubayda aqueduct system used to supply Mecca’s water had fallen into disrepair. In 1878, Sultan Abdülhamid II ordered the creation of a commission of Hijazi notables to solicit charitable contributions from across the Islamic world in order to fund the needed repairs. During the early 1880s, the Ottoman governor of the Hijaz, Osman Nuri Pa?a, oversaw a major overhaul of the Hijaz’s water supply. Major repairs and extensions to the Hijaz’s network of water channels, fountains, and cisterns were also needed to supply clean water to Arafat, Mina, and Muzdalifa. And Jidda’s water shortage was so acute that even prior World War I it had become greatly dependent on distillation and condenser machines used to convert seawater into potable water. This paper will attempt to demonstrate how late Ottoman hydro-centralization projects were resurrected and directly referenced by the early Saudi state, British engineering firms, and the American geologists and oil men who helped shape the petro-state we now know.