Groundwater overdraft is a major problem globally and has been a persistent and growing problem in California for decades. This overdraft is predominantly driven by the economic value of water for agricultural production and cities. Spurred by the recent drought, California passed legislation requiring the elimination of groundwater overdraft by 2040. To explore potential water supply effects of ending long-term groundwater overdraft in California’s Central Valley, we compared several water policies with historical and warmer–drier climates, employing a statewide hydroeconomic optimization model, CALVIN, in our new paper.