California Water Views

On March 12, 2026, the Department of Water Resources (DWR) announced via press release and bulletin the release of its California Groundwater: Bulletin 118 – Update 2025 (2025 Update). Bulletin 118 represents “the State’s official and most comprehensive report of groundwater monitoring, conditions, and management across California.”

The 2025 Update is the third Bulletin 118 issued by DWR under the Sustainable Groundwater Management Act (SGMA), with DWR publishing an interim update in 2016 and the first full update under SGMA in 2020. Pursuant to Water Code § 12924, DWR must publish updates every 5 years. The 2025 Update process included public comments and a public webinar.

DWR has provided a substantial number of resources to help interested parties understand the 2025 Update. That includes a fact sheet; a short summary document; and a data and resources page that includes the full report, all appendices, and a “highlights” document that summarizes the full update. The 2025 Update itself is incredibly detailed and includes key appendices such as Appendix A, which summarizes all findings and recommendations, and Appendix J, which summarizes the data on project and management actions.

The 2025 Update includes new and expanded topics, including:

• A more comprehensive analysis of the state’s groundwater resources, which was informed by data generated through implementing SGMA (and other efforts);
• More detail on the impacts of extreme events such as droughts and high levels of precipitation as well as climate change more generally;
• New information and data on groundwater recharge and land subsidence;
• Updates on SGMA implementation;
• A topic-based index; and
• Updated recommendations and summary of key findings.

Key findings from the 2025 Update include:

• Groundwater basins represent the largest and least expensive storage option for the state;
  • Storage capacity exceeds 1 billion acre-feet
• Groundwater usage represents about 40% of the state’s usage during average years and 60% during dry years;
  • The state’s recent extreme droughts have led to increased reliance;
• More than 32 million people rely on groundwater for at least a portion of their supply;
• Groundwater usage is roughly 79% agriculture, 19% urban, and 2% managed wetlands;
• There are signs that groundwater levels are improving;
• Land subsidence remains a significant problem; and
• SGMA has led to more than 1,500 local projects and management actions.
  • Costs for these projects and management actions are estimated to be in the billions

On top of the 5-year updates, DWR also issues semi-annual updates (data and reports for which can be found here). It expects to issue the Spring 2026 update “soon”. These semi-annual reports are issued to provide more updated and dynamic information to guide parties in complying with SGMA and tracking its progress.