Saudi Arabia experienced extensive and rapid developments in all sectors during the last two decades with a rapid and vast increase in water demand. The country follows the sacred principles of the Muslim law "Shari'a," where water is considered the common entitlement of all Muslims. In the last decades, however, the traditional methods for satisfying the limited water needs have been modified in accordance with Islamic laws to meet the rise in water demand and organize water management issues. Legislation and institutions, new water pricing policies, demand reduction techniques, and regulations for well drilling have been introduced Support of cultivation of some crops has been modified to minimize irrigation water use. and modern irrigation techniques have been practiced to reduce water losses and demand. The Council of Muslim Leading Scholars has given pioneering examples of the flexibility of Islam by issuing a special Fatwa to regulate the reuse of treated effluents for different purposes. This has promoted wastewater recycling by the public. The Islamic principles used in Saudi Arabia have helped to improve water demand management, and the gained experience can benefit other countries.