California's Groundwater Update 2025 (Bulletin 118)
California's Groundwater: Bulletin 118 Updates (CalGW Updates) are California's foremost technical publications on groundwater in the state. The Department of Water Resources is legislatively mandated by Water Code Section 12924 to publish CalGW Updates every 10 years. This page includes the DRAFT publication of California's Groundwater: Bulletin 118 - Update 2025 (CalGW Update 2025). The Department of Water Resources released this draft publication on October 20th, 2025, opening a 45-day public comment period, and will hold a public webinar on November 4, 2025 to answer questions and solicit comments. Public comments can be emailed to CalGW@water.ca.gov and will be accepted through Friday, December 5, 2025. The draft publication contains a summary Highlights (available in English and Spanish) and a detailed statewide report (Chapters 1 – 6), which features current knowledge of groundwater resources including information on the location, characteristics, use, management status, and conditions of the state’s groundwater. Also included in this draft release is an info-graphic summary of the ten hydrologic regions, showing regional groundwater at a glance (Chapter 7) and some draft appendices including: findings and recommendations that support the future management and protection of groundwater; a glossary of terms; reference materials; and an update on land subsidence in California. For more information on CalGW Updates, historical publications, and supporting information products that include the CalGW Live website and California’s Groundwater: Semi-Annual Updates, please visit: https://water.ca.gov/programs/groundwater-management/bulletin-118.
Data files
Supporting files
| Data title and description | Access data | File details | Last updated |
|---|---|---|---|
California's Groundwater: Bulletin 118 - Update 2025 DRAFT Highlights (English) DRAFT A stand-alone summary document describing the value, current state, and challenges of groundwater conditions and management in California, including findings and recommendations to advance sustainable groundwater management. | PDF | 10/21/25 | |
Agua Subterránea de California 2025: Boletín 118 - Borrador Puntos Sobresalientes (Español) Borrador Agua Subterránea de California 2025 – Puntos Sobresalientes presenta un resumen de alto nivel del Informe Estatal, incluyendo un numero de hallazgos y recomendaciones. | PDF | 10/21/25 | |
California's Groundwater: Bulletin 118 - Update 2025 DRAFT Statewide Report (Chapters 1 - 6) DRAFT This PDF includes a detailed report on the current state of knowledge of groundwater resources including information on the location, basin characteristics, water use, management, climate change vulnerability, monitoring, and conditions of the state’s groundwater. | PDF | 10/21/25 | |
California's Groundwater: Bulletin 118 - Update 2025 DRAFT Hydrologic Region Summaries (Chapter 7) DRAFT 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. Please note that this file is large and will take a moment to download. | PDF | 10/21/25 | |
DRAFT Appendix A: Findings and Recommendations DRAFT This appendix provides a list of all findings and recommendations included in the Highlights document. | PDF | 10/21/25 | |
DRAFT Appendix B: Glossary DRAFT This appendix provides a list of key groundwater terms and definitions found in CalGW Update 2025. | PDF | 10/21/25 | |
DRAFT Appendix D: Citations, Reference Materials, and Links DRAFT This appendix contains the citations identified throughout CalGW Update 2025 and a comprehensive list of recommended additional reference material and data. This appendix may be updated periodically to reflect new information. | PDF | 10/21/25 | |
DRAFT Appendix I: Land Subsidence DRAFT This appendix provides detailed information on select sites modeled for projected future subsidence, as well as an updated inventory of major subsiding areas in the state. It is an update of the Land Subsidence from Groundwater Use in California (Borchers and Carpenter 2014) report, originally prepared for the California Water Foundation. This report was prepared for DWR by INTERA, James Borchers and Luhdorff & Scalmanini Consulting Engineers. | PDF | 10/21/25 |