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 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.
Keywords
climate change, groundwater, planning and management, water supply