What is the import of California’s Sustainable Groundwater Management Act of 2014 (“SGMA”)? It is acknowledgement that groundwater consumption is drastically outpacing aquifer replenishment and that new tools are necessary to resolve this issue. However, there is justifiable concern that the SGMA is ill-equipped to tackle sustainable groundwater management. Additionally, the timing of the SGMA’s adoption raises questions as to the Legislature’s motives, especially when it has remained silent for more than a century with respect to groundwater conservation. While the problem appears to be a tragedy of the groundwater commons (potentially remedied by market-based incentives and/or collective action), it is in fact much more complicated. As this paper argues, the problem is rooted in the interplay between the over-allocation of Constitutionally protected groundwater use rights, the American common law system and its independent regimes for surface water and groundwater resources (despite hydrogeological interconnectedness), the legislative process, severe climate-induced drought, and a significant lag between technological advancement and legal precedent. Only through state powers like eminent domain (by reacquiring and redistributing use rights) can the state prevent unbridled groundwater extraction.