… Under SGMA, which is implemented by local agencies, groundwater basins have until 2040 or 2042 to achieve sustainability. But since 2020 or 2022, depending on local conditions, groundwater agencies have been required to prevent “undesirable results” such as land subsidence and household wells running dry. In the San Joaquin Valley, where the aquifers are especially depleted, preventing those outcomes requires major changes ahead of the law’s final deadline. Groundwater agencies covering much of the valley adopted pumping limits, or allocations, within the past few years as the state began cracking down on subbasins with inadequate plans. … The pumping reductions required by SGMA could cause as much as 20% of the San Joaquin Valley’s farmland to be taken out of production by 2040, according to a report by the Public Policy Institute of California.