i03 Adjudicated Areas

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.