This chapter examines the right to water within Islamic thought and its tangible expression in Islamic-Iranian cities. Rooted in a theocentric worldview, Islamic environmental theory regards water as a divine gift and communal trust, emphasizing justice, equity, and sustainability. The Quran and Hadith establish water as a shared resource, with fundamental rights including shafa (right of thirst) and shirb (right to irrigate). Islamic water management prioritizes drinking and domestic use, prohibits waste and pollution, and integrates conservation as a moral duty. Historically, Muslim civilizations developed sophisticated water technologies—such as qanats, norias, sabils (public fountains), and dams—that balanced human needs with ecological limits. In Iranian cities, water scarcity shaped urban morphology and gave rise to a distinctive “water architecture” where flowing, erupting, and stagnant water symbolised spiritual concepts like paradise, purity, and the transient nature of life. Examples from Kashan, Isfahan, and Tehran illustrate how water was integrated into gardens, mosques, palaces, and public baths. The chapter concludes that recognising the right to water in Islamic thought offers a framework for sustainable urban development, aligning faith, culture, and practicality to ensure clean and affordable water as a cornerstone of human dignity and environmental stewardship.