Ottoman Empire, after the annexation of Hejaz, during the period of the first Suleyman, has made huge investments in order to provide the uninterrupted and fluid water needs of both cities. Especially in 1530 and 1570, spending large amounts of money by Suleyman the Magnificent and his daughter Mihrimah Sultan for the Ayn-i Zubeydah led to maintain for many years as the most important water source of Macca. In a similar vein, immediate repairs were made tenderly and precisely resulting from natural conditions, unexpected events and renewal needs while spending large amount of money for Zamzam Well and Ayn-i Zubayda in Madinah, In general, the basic needs of two primary water sources were provided by the state. Financing water services for the route of pilgrimage and works such as fountain, water distribution, water withdrawal from wells in Holy Cities were performed by the foundations. Starting from Sokullu Mehmed Pasha to current times dozens of foundations for this purpose have been established. Some of them are as follows: Fountains and foundations were built in various places in Mecca and Medinah, The consecration of Hatice Turhan Sultan‟s 7800 ghrush for providing the needs of Hacilar and Haremeyn. The foundation of Lala Mustafa Pasha in order to build fountains and water pools in Madinah. The construction of a new waterway in Mecca and establishment of foundations in Medina due to repair possible hitches immediately through following the path of the 'Ayn-ı Zerka waterway by Kemankesh Mustafa Pasha In our study, primarily, at the beginning of XIIIth of Hijri year, in other words, in terms of Gregorian calendar, at the end of the XVIIIth century, the repair and maintenance activities for basic water resources in Mecca and Medina and established foundations with the aim of providing water services to the pilgrims and local folk will be discussed.