Adjudication is a form of groundwater management in California through the courts. When groundwater resources do not meet water demands in an area, landowners may turn to the courts to determine how much groundwater can be rightfully extracted by each overlying landowner or appropriator. The court typically appoints a Watermaster to administer the judgment and to periodically report to the court. As of 2017 there were 29 adjudicated groundwater basins in California, with the majority of the adjudications located in Southern California in the South Coast hydrologic region. The majority of groundwater rights adjudications in California imposes extraction limits and/or initiates management actions in the event of declining groundwater levels or water quality degradation. It should be noted that the primary objective of an adjudication is to provide a proportionate share of the available groundwater to the users within the basin so it can be extracted without having adverse effects to existing groundwater supplies. Environmental concerns were not considered when most of the judgments were written. Areas designated to be treated as adjudicated areas as defined in Water Code Section 10720.8.
