This paper engages with emergent conceptualizations of political-industrial ecology to understand the politics surrounding how the volume, composition, and material throughput of stormwater in Los Angeles is calculated and applied by experts. The intent is to examine the unfolding relationship between the volume and material flow of stormwater, and the social, political, and technical practices involved in identifying stormwater as a new and underutilized water resource. Specifically, it seeks to understand how the active processes of calculating the metabolic inflows and outflows of stormwater in Los Angeles serve as a way for the city to render value and meaning to the flows of stormwater. I suggest that the ways urban metabolisms are calculated reflect a volumetric approach to environmental governance that serves to achieve certain political goals. I refer to this type of governance as volume control—a way of organizing technopolitical interventions around overcoming problems related to the volume of resources flowing and circulating into, through, and out of cities and industrial systems. I argue that understanding this form of governance relies on taking a political-industrial ecology approach that accounts for both the social and material dimensions of resource flows. While the categories and motivations of stormwater governance remain contested over time and space, it is shown that stormwater in Los Angeles needs to be understood in relation to the ecological systems and scientific, political, and cultural practices designed to make it into a resource and align with existing patterns of growth and development.