Growing into Water Conservation? Decomposing the Drivers of Reduced Water Consumption in Las Vegas, NV

Increasing population and drought have lead to growing concerns about water scarcity across the US despite a long decline in per-capita consumption. To what extent is this decline the result of water policy vs. other exogenous changes? Many municipalities implement multiple water-focused policies simultaneously – while still subject to other exogenous drivers – so it is important to pair policy evaluations with approaches that examine multiple drivers of water use. The importance of water policy, infrastructure change, and broader technological and demographic trends in influencing water demand has not been measured. We demonstrate a novel method for decomposing multiple drivers of consumption using a dataset of neighborhood water consumption, home infrastructure characteristics, and vegetation in Las Vegas. The largest measureable factor driving conservation for Las Vegas as a whole is lower consumption from new homes, while in established neighborhoods it is declining vegetation area. However, factors we measure directly account for only half of the observed consumption decline. This provides indirect evidence that consumption declines coincident with a drought alert, increased water waste enforcement, and other policy responses also played an important role in conservation. An array of approaches directed at both infrastructure and behavior can effectively reduce consumption.