WISER › Extension Materials & Guides › California County Water Series
Understanding California Water, County by County
Clear, practical, and science-based resources that explain where water comes from, how it is used and managed, and the challenges shaping water resilience across California’s diverse counties. Developed through WISER, the series combines statewide context with county-specific data, maps, planning resources, and local perspectives.
About the Series
Water conditions vary significantly across California’s 58 counties. Communities rely on different combinations of groundwater, rivers, reservoirs, imported water, and local surface supplies. Water use, quality, infrastructure, governance, and exposure to drought, flooding, wildfire, and other hazards also differ from one county to another.
Each county factsheet brings together accessible information about water supply, water use, watersheds, groundwater, water quality, planning, and resilience. The resources are designed for residents, educators, community organizations, water professionals, and decision-makers.
The series will continue to grow as new county factsheets are researched, reviewed, designed, and published.
A statewide factsheet series for California’s 58 counties.
Explore California Counties
All 58 California counties are listed below in alphabetical order. New PDF links can be added directly as each factsheet is completed and published.
Available Future release
Alameda–Madera
- Alameda County Future release
- Alpine County Future release
- Amador County Future release
- Butte County Future release
- Calaveras County Future release
- Colusa County Future release
- Contra Costa County Future release
- Del Norte County Future release
- El Dorado County Future release
- Fresno County Future release
- Glenn County Future release
- Humboldt County Future release
- Imperial County Future release
- Inyo County Future release
- Kern County → Available
- Kings County Future release
- Lake County Future release
- Lassen County Future release
- Los Angeles County Future release
- Madera County Future release
Marin–San Joaquin
- Marin County Future release
- Mariposa County Future release
- Mendocino County Future release
- Merced County Future release
- Modoc County Future release
- Mono County Future release
- Monterey County Future release
- Napa County Future release
- Nevada County Future release
- Orange County Future release
- Placer County Future release
- Plumas County Future release
- Riverside County Future release
- Sacramento County Future release
- San Benito County Future release
- San Bernardino County Future release
- San Diego County Future release
- San Francisco County Future release
- San Joaquin County Future release
San Luis Obispo–Yuba
- San Luis Obispo County Future release
- San Mateo County Future release
- Santa Barbara County Future release
- Santa Clara County Future release
- Santa Cruz County Future release
- Shasta County Future release
- Sierra County Future release
- Siskiyou County Future release
- Solano County Future release
- Sonoma County Future release
- Stanislaus County Future release
- Sutter County Future release
- Tehama County Future release
- Trinity County Future release
- Tulare County Future release
- Tuolumne County Future release
- Ventura County Future release
- Yolo County Future release
- Yuba County Future release
Follow New County Releases
Visit WISER’s digital ecosystem to find new county factsheets, videos, stories, and educational content—and follow our social media channels as the California County Water Series grows.
Project Team and Contributors
The California County Water Series brings together student research, science communication, UC Cooperative Extension expertise, and project coordination through the California Institute for Water Resources.
Student Research & Science Communication
Natalia Wilson
Natalia leads student research, data collection, content development, and science communication for county factsheets, maps, visual resources, and accessible educational materials.
UC Cooperative Extension Contributors
Laura Garza, Esther Lofton, and Lal Singh
Laura, Esther, and Lal contribute regional knowledge, technical guidance, and review to help ensure that county materials are accurate, relevant, and useful for California communities.
Project Coordination
Erik Porse, Hope Hauptman, and Erika Cassio
Erik, Hope, and Erika coordinate the series’ research direction, county framework, editorial development, technical review, student mentorship, and connection to CIWR and WISER programs.