Cities in the American Southwest face growing water scarcity, yet they respond to this challenge in strikingly different ways. This thesis argues that these differences cannot be explained by hydrology or regulation alone. Instead, urban planning form shapes how scarcity becomes institutionally visible and how public administrators define, interpret, and manage environmental limits. Using Tucson and Phoenix as contrasting cases, the study combines GIS spatial analysis with policy interpretation to trace how development patterns, infrastructure systems, and planning histories structure governance logic. Tucson’s compact form and long-standing conservation ethos make scarcity visible and support restraint-based governance. Phoenix’s expansive, infrastructure-driven form frames scarcity as a technical problem solvable through augmentation. These governance orientations reflect deeper institutional ideologies and shape administrative capacity, coordination, and long-term policy choices. The findings highlight the need for integrated planning-governance approaches and offer a framework for understanding how cities can build more adaptive and resilient water systems in an era of climate uncertainty.