Understanding the physical characteristics and cultural connotations of water is fundamental in obtaining a more in-depth view of the relationship between monastic lives and spaces. This study moves from several case studies to two case comparisons to a synthesis of two space prototypes to investigate how water management evolved into spatial water thought and became a common reference for monastic lives and spaces. Cistercian and Han Buddhist monasteries are investigated and considered to share many similarities in the internal institutional model of monks’ lives, as well as their corresponding architectural core values. They are suitable cases for exploring this research idea. In Cistercian and Han Buddhist monasteries, the role of water in monks’ lives and spaces is mainly reflected in the following aspects: 1) the form of the water body shaped the monastic spatial morphology in site selection; 2) the structure of water flow was closely related to spatial order and affected the spatial distribution; and 3) the performance of the water status formatted the connotation of space. This article attempts to depict a complete picture of the relationship between monastic lives and spaces from the perspective of water. Under the common pursuit of self-sufficient retreat life, water management was the common strategy for monastic venues to turn the wilderness into paradise refuges. Findings of this article show that the water culture of self-sufficiency and self-cleaning is the common reference, a shared universal value, and common parts of the spatial thought of the two monastic venues. Awareness of the importance of water in monastic lives and spaces helps us to pay attention to the relationship between the water environment and monastic venues. The research findings are linked to the current requirements of historical monasteries’ preservation, restoration, and even reconstruction, which are fundamental in maintaining the sustainable development of monastic lives and spaces.