Engineering Geologists Sonja Dreuth (center) and Nicholas Vadpey from the California Department of Water Resources North Central Region Office, in the Division of Regional Assistance, collect groundwater quality samples using a no-purge bailer water sampling device at a monitoring well at the Sacramento Bypass in Yolo County. Student Assistant Guadalupe Ferreyra (right), who also monitors the well, lends support. Photo taken August 30, 2024.
Expanded Groundwater Data is Helping Improve Understanding of Groundwater Conditions Across California
SACRAMENTO, Calif. – California is now collecting more groundwater data than ever before as highlighted in the Semi-Annual Groundwater Conditions Update released today by the Department of Water Resources (DWR). Made up of groundwater data gathered over the past year from various DWR tools and annual reports from local groundwater sustainability agencies (GSAs), the Update includes information on statewide groundwater levels, groundwater storage, recharge, land subsidence, well infrastructure and the status of California’s groundwater conditions.
“When it comes to water management in California, it’s important that state and local water decisions are made with the latest, most accurate data in mind. Thanks to the information collected from our local partners, we’re gaining more knowledge about the challenges our groundwater-dependent communities are facing and their progress towards meeting the overall goals set by the Sustainable Groundwater Management Act,” said Paul Gosselin, DWR Deputy Director of Sustainable Water Management.
Water Year (WY) 2024 marked a significant milestone for groundwater management in California, as the state celebrated the 10-year anniversary of the Sustainable Groundwater Management Act (SGMA), the statewide regulatory framework established to ensure the sustainability of our groundwater basins by 2040. Over the course of 2024, the state received average precipitation, helping sustain recharge efforts after the exceptionally wet 2023. These last three years (2023, 2024, and 2025) have seen continued increases in groundwater storage. Water Year 2024 increased by 2.2 million acre-feet reported across 98 basins – a direct result of state and local actions to capture and store more water underground.
However, the first five months of WY 2025 were notably dry across much of the state, especially in the Central Valley and southern regions. In contrast, portions of Northern California experienced above-average or record-setting rainfall. These sharp contrasts highlight California’s weather shifts and increasing need for dynamic water management.
Additional findings from today’s report include:
Groundwater Management
- Groundwater storage increased by 2.2 million acre-feet reported across the 97 basins during WY 2024. This increase reflects actions such as capturing and recharging high flows during winter storms, expanding recharge basins, improving groundwater monitoring, and coordination among local agencies to reduce groundwater pumping.
SGMA Implementation
- Local GSAs are executing Groundwater Sustainability Plans (GSPs) that incorporate recharge projects, demand reduction, efficiency programs, and land use coordination.
- GSAs are expanding monitoring networks and using annual reports to track key sustainability indicators such as groundwater levels, subsidence, use patterns, and recharge volumes.
- DWR is investing in tools like InSAR, Airborne Electromagnetic (AEM) surveys, advanced modeling, and telemetry to improve data quality and inform water management decisions.
- Groundwater storage in the Central Valley remains highly sensitive to drought and wet periods.
Land Subsidence
- Active land subsidence continues to be observed in the Sacramento River, San Joaquin River, and Tulare Lake Hydrologic Regions. DWR continues to expand data collection on subsidence in these areas and plans to release guidance for GSAs later this year.
Dry Wells
- Fewer dry wells were reported in WY 2024 compared to WY 2021, WY 2022, and WY 2023.
DWR is now entering a new era of groundwater sustainability driven by action and implementation of GSPs. Throughout this process, DWR continues to provide support to help GSAs implement their plans through improved communications utilizing facilitation support for sensitive or challenging meetings, and translation services to improve critical information sharing. Additionally, DWR will release guidance on depletions of interconnected surface water and subsidence later this year. DWR’s goal with these two documents is to provide local groundwater sustainability partners with the information and direction they need to understand how to address the impacts of overdraft on our groundwater basins and support our water supply for future generations.
Across the state, 85 percent of Californians depend on groundwater for some portion of their water needs, with groundwater also acting as a buffer and supplying up to 60 percent of the state’s water supply during drought years. While the water beneath our feet is unseen and often overlooked, sustainable management of this resource is critical for long-term water supply reliability. By monitoring and tracking conditions and collecting new data, state and local agencies can better manage water resources during average and wet years to ensure groundwater will be available as a buffer during dry years.
For more information:
- DWR Semi-Annual Groundwater Conditions Updates
- California's Groundwater (Bulletin 118)
- California’s Groundwater Live
- Sustainable Groundwater Management Act (SGMA)
- Groundwater Recharge
Contact:
Allison Armstrong, Information Officer, Public Affairs, Department of Water Resources