California's Groundwater Update 2025 (Bulletin 118)

A three-page overview describing the structure and key content of CalGW Update 2025.

The CalGW Update 2025 Highlights is a stand-alone summary describing the value, current state, and challenges of groundwater conditions and management in California, including findings and recommendations to advance sustainable groundwater management.

Resumen general del Informe Estatal, describiendo el valor, estado actual, y desafíos de las condiciones y el manejo del agua subterránea en California, incluyendo recomendaciones para avanzar en su gestión sostenible.

This PDF includes the full CalGW Update 2025 statewide report, including Chapters 1 – 7. Chapters 1 – 6 provide a detailed report on the current state of knowledge of groundwater resources in California, and Chapter 7 includes groundwater and groundwater-related information for each of California's 10 hydrologic regions.

This PDF includes a detailed report on the current state of knowledge of groundwater resources in California, including information on the location, basin characteristics, water use, management, climate change vulnerability, monitoring, and conditions of the state’s groundwater.

Chapter 7 Groundwater at a Glance, Hydrologic Region Summaries includes groundwater and groundwater-related information for each of California's 10 hydrologic regions (HRs). The goal of the regional summaries is to provide “groundwater at a glance,” a snapshot of data, figures, and information at the HR scale. These regional summaries include an overview of demographics, groundwater and land use, climate change vulnerability, water shortage vulnerability, groundwater management, groundwater recharge, well infrastructure, groundwater levels, groundwater quality, and local assistance and local projects. Each summary concludes with a map of each HR and list of groundwater basins. The HR summaries include information presented in Chapters 1 through 6 along with additional region-specific information.

The CalGW Update 2025 Factsheet acts as a quick reference for California’s groundwater resources and a summary of what’s new in the CalGW Update 2025.

La ficha informativa de la actualización de CalGW 2025 actúa como referencia rápida para los recursos de agua subterránea de California y un resumen de las novedades en la actualización de CalGW 2025.

The Key Topics Index acts as a quick reference for key topics found in the CalGW Update 2025.

This appendix provides a list of all findings, recommendations, and supporting actions included in CalGW Update 2025 Highlights, along with progress status of actions as of February 2026.

This appendix provides a list of key groundwater terms and definitions found in CalGW Update 2025.

The appendix provides the Methods and Assumptions used to create the figures and tables found in CalGW Update 2025.

This appendix contains the citations, as well as links to reference materials, identified throughout CalGW Update 2025.

This appendix provides a simplified summary of all basin maps and tables, organized by Hydrologic Region.

This appendix includes a dataset summarizing California water use information, population, and land use data developed for the California Water Plan for water years 2002 through 2021. This information was used for content in CalGW Update 2025 Chapter 4.

This appendix includes supplemental data for area and population by hydrologic region.

This appendix includes supplemental data for area and hydrologic region assignment by basin.

This appendix includes supplemental data for groundwater related county ordinances, organized by county.

This appendix provides access to California’s Groundwater Semi-Annual Updates, which can also be found at: https://data.cnra.ca.gov/dataset/california-s-groundwater-semi-annual-conditions-updates.

Update on Land Subsidence in California builds on Land Subsidence from Groundwater Use in California (Borchers et al., 2014), originally prepared for the California Water Foundation, by incorporating more than a decade of additional data, advances in monitoring and analytical tools, an updated summary of land subsidence impacts, and the regulatory framework established under SGMA. This report also supplements DWR’s Land Subsidence Best Management Practices (BMP) by further elaborating on recommended monitoring, analysis, and modeling approaches to evaluate land subsidence processes and management actions. This report includes data compilations and one-dimensional land subsidence modeling simulations for 50 long-term monitoring sites throughout the Central Valley. The modeling files and DWR’s land subsidence datasets are available on the California Natural Resources Agency Open Data Platform at https://data.cnra.ca.gov/. Additional resources on land subsidence are available on DWR’s website at https://water.ca.gov/Programs/Groundwater-Management/Subsidence/. This report was prepared for DWR by INTERA and James Borchers.

This appendix presents a comprehensive summary of Projects and Management Actions (PMAs) reported through the Sustainable Groundwater Management Act (SGMA) Portal’s PMA Module (https://sgma.water.ca.gov/portal/projects/submitted). The information reflects the dataset available as of April 2025 and is intended to provide a baseline understanding of the scope, type, and potential benefits of PMAs across the state.

The CalGW Live website provides the most relevant and recent groundwater information. The webpage includes a series of interactive dashboards which allow users to interact and customize what groundwater data they would like to view. Users can filter the data by address, county, groundwater basin, or hydrologic region to see unique data summaries. CalGW Live has been developed for a variety of users including groundwater managers, governmental agencies, well owners, non-governmental organizations, water policy makers, and members of the public interested in groundwater.

This zipped folder contains select datasets (as Excel workbooks, CSVs, and shapefiles) used in table/figure creation for Chapter 1. Only snapshot datasets that include an analysis altering a public dataset are included. Folder titles follow a naming convention that lists Chapter (C) number first, followed by Figure (F) or Table (T) number. In some cases, not all figure or table numbers are included in the folder name and thus include a Read Me text file as part of the download. See also, Appendix C Methods and Assumptions. For the most current groundwater data available, please see California’s Groundwater Live website: https://calgwlive.water.ca.gov/.

This zipped folder contains select datasets (as Excel workbooks, CSVs, and shapefiles) used in table/figure creation for Chapter 2. Only snapshot datasets that include an analysis altering a public dataset are included. Folder titles follow a naming convention that lists Chapter (C) number first, followed by Figure (F) or Table (T) number. In some cases, not all figure or table numbers are included in the folder name and thus include a Read Me text file as part of the download. See also, Appendix C Methods and Assumptions. For the most current groundwater data available, please see California’s Groundwater Live website: https://calgwlive.water.ca.gov/.

This zipped folder contains select datasets (as Excel workbooks, CSVs, and shapefiles) used in table/figure creation for Chapter 3. Only snapshot datasets that include an analysis altering a public dataset are included. Folder titles follow a naming convention that lists Chapter (C) number first, followed by Figure (F) or Table (T) number. In some cases, not all figure or table numbers are included in the folder name and thus include a Read Me text file as part of the download. See also, Appendix C Methods and Assumptions. For the most current groundwater data available, please see California’s Groundwater Live website: https://calgwlive.water.ca.gov/.

This zipped folder contains select datasets (as Excel workbooks, CSVs, and shapefiles) used in table/figure creation for Chapter 4. Only snapshot datasets that include an analysis altering a public dataset are included. Folder titles follow a naming convention that lists Chapter (C) number first, followed by Figure (F) or Table (T) number. In some cases, not all figure or table numbers are included in the folder name and thus include a Read Me text file as part of the download. See also, Appendix C Methods and Assumptions. For the most current groundwater data available, please see California’s Groundwater Live website: https://calgwlive.water.ca.gov/.

This zipped folder contains select datasets (as Excel workbooks, CSVs, and shapefiles) used in table/figure creation for Chapter 5. Only snapshot datasets that include an analysis altering a public dataset are included. Folder titles follow a naming convention that lists Chapter (C) number first, followed by Figure (F) or Table (T) number. In some cases, not all figure or table numbers are included in the folder name and thus include a Read Me text file as part of the download. See also, Appendix C Methods and Assumptions. For the most current groundwater data available, please see California’s Groundwater Live website: https://calgwlive.water.ca.gov/.

This zipped folder contains select datasets (as Excel workbooks, CSVs, and shapefiles) used in table/figure creation for Chapter 6. Only snapshot datasets that include an analysis altering a public dataset are included. Folder titles follow a naming convention that lists Chapter (C) number first, followed by Figure (F) or Table (T) number. In some cases, not all figure or table numbers are included in the folder name and thus include a Read Me text file as part of the download. See also, Appendix C Methods and Assumptions. For the most current groundwater data available, please see California’s Groundwater Live website: https://calgwlive.water.ca.gov/.