North Lahontan

California's Groundwater Update 2025 (Bulletin 118)

California Department of Water Resources (DWR) | October 20th, 2025

California’s Groundwater: Bulletin 118 — Update 2025 (CalGW Update 2025) is a compendium of statewide data and information on the occurrence, nature, use, and conditi

California’s Groundwater: Bulletin 118 — Update 2025 (CalGW Update 2025) is a compendium of statewide data and information on the occurrence, nature, use, and conditions of California’s groundwater resources and management. Chapters 1-6 Chapter 7 Appendix A: Findings and Recommendations Appendix B: Glossary Appendix D: Citations, Reference Materials, and Links Appendix I: Land Subsidence  

California's Rivers and Streams

Public Policy Institute of California (PPIC) | January 26th, 2026

California's Water Supply Strategy: Adapting to a Hotter, Drier Future

California Department of Water Resources (DWR) | August 16th, 2022

California's Water Supply Strategy: Adapting to a Hotter, Drier Future

Office of Governor Gavin Newsom | August 11th, 2022

California's Water–Energy Relationship

California Energy Commission (CEC) | November 1st, 2005

This report examines the dynamic give-and-take relationship between California’s water and energy resources. Among many other issues, this staff report examines the s

This report examines the dynamic give-and-take relationship between California’s water and energy resources. Among many other issues, this staff report examines the state’s water sector and its energy use, along with changes likely to occur in the future.

California’s Groundwater Conditions Semi-Annual Update: October 2022

California Department of Water Resources (DWR) | October 15th, 2022

This report is a semi-annual update of the annual Groundwater Conditions Report published in March 2022 and part of DWR’s California’s Groundwater (Bulletin 118). Wat

This report is a semi-annual update of the annual Groundwater Conditions Report published in March 2022 and part of DWR’s California’s Groundwater (Bulletin 118). Water Year 2022 groundwater data used in this report includes data received electronically by DWR as of August 31, 2022.

California’s Groundwater Conditions: Semi-Annual Update

California Department of Water Resources (DWR) | October 13th, 2026

California’s groundwater conditions generally stabilized in Water Year (WY) 2026, though persistent effects of long-term groundwater depletion remain, and hydrologic va

California’s groundwater conditions generally stabilized in Water Year (WY) 2026, though persistent effects of long-term groundwater depletion remain, and hydrologic variability continues. WY 2026 began with near-average precipitation and snow conditions, but a warm, dry spring reduced statewide precipitation to below average and contributed to the second-lowest April snowpack on record. These conditions highlight a growing challenge for groundwater management: as California experiences greater variability in the timing and form of precipitation, capturing water when it is available and storing it for future dry periods becomes increasingly important. 

California’s Groundwater Conditions: Semi-Annual Update, October 2023, Fall Bulletin 118 Information Update

California Department of Water Resources (DWR) | October 12th, 2023

This semi-annual report presents data received by DWR as of August 31, 2023, and partially reflects the impacts of recent storms, flooding, and natural and managed aquife

This semi-annual report presents data received by DWR as of August 31, 2023, and partially reflects the impacts of recent storms, flooding, and natural and managed aquifer recharge. However, it should be noted that groundwater response is a slow process and takes months to years to fully respond to changes in surface water conditions.

California’s Groundwater: Bulletin 118 — Update 2025 Highlights

California Department of Water Resources (DWR) | October 20th, 2025

California’s Groundwater: Bulletin 118 — Update 2025 (CalGW Update 2025) serves as the most up-to-date and comprehensive compendium of statewide data and information

California’s Groundwater: Bulletin 118 — Update 2025 (CalGW Update 2025) serves as the most up-to-date and comprehensive compendium of statewide data and information on the occurrence, nature, uses, management, climate change vulnerability, monitoring, and conditions of California’s groundwater resources. Building on the legacy of Bulletin 118 and past California Water Plans, CalGW Update 2025 synthesizes recent data — available up to December 2023 — and closes key knowledge gaps to inform more effective statewide groundwater planning and decision-making.  CalGW Update 2025 consists of this Highlights document and a detailed statewide report, supported by a series of appendices. 

California’s Stream Flow Monitoring System Is Essential for Water Decision Making

University of California, Berkeley (UC Berkeley) | April 1st, 2018

With California’s drought risk, flood risk, and demand for water all increasing, effective monitoring is more important than ever to water decision making. Str

With California’s drought risk, flood risk, and demand for water all increasing, effective monitoring is more important than ever to water decision making. Stream gages monitor the most basic vital sign of California’s waterways—stream flow.1 Stream flow data support day-to-day decisions about how to manage water and operate water infrastructure. In turn, those decisions have important implications for flood control and the water supplies upon which residential, industrial, agricultural, and environmental water users depend. Stream flow information also provides technical insights into basin hydrology, and those insights aid long-term water planning. As pressures on the state’s water systems intensify, the need for accurate and timely stream flow information will continue to grow. Opportunities for better water management created by groundbreaking legislation such as the Sustainable Groundwater Management Act (SGMA), the Open and Transparent Water Data Act, and Proposition 1 will be severely limited without an effective network of continuous stream gaging.