By Esther N Lofton, Laljeet S Sangha, Laura E Garza Diaz, UCANR
California’s water systems are at a pivotal moment. The pressures of climate change, population growth, aging infrastructure, and persistent inequities in water access are converging to create unprecedented challenges. At the same time, the state is moving forward with an ambitious, integrated vision for a resilient future, embodied in the California Water Plan Update 2023 (CWP-2023).
Building on a long-standing tradition of five-year updates, CWP-2023 recognizes the urgency of climate impacts, the necessity of watershed-scale thinking, and the central role of equity in water policy. For the first time, it includes a chapter co-authored with California Native American Tribes, ensuring Indigenous knowledge, priorities, and rights are integrated into statewide planning.
The plan serves as a strategic framework. Local and regional agencies that align their actions with its strategies are better positioned to secure state and federal resources, build inter-agency collaborations, and deliver multi-benefit projects. This alignment is already visible in several regions; most notably, Los Angeles County, which offers one of the most comprehensive local applications of the state’s vision. Other examples include Orange County, San Diego, Santa Clara, Sacramento, the Santa Ana River watershed, and Sonoma County, each adapting CWP-2023 priorities to their unique hydrologic, governance, and community contexts.
The California Water Plan 2023: Vision and Priorities
At its core, CWP-2023 is built around three coequal objectives:
- Addressing climate urgency; facing an increasingly variable hydrologic cycle through adaptive infrastructure, flexible operations, and robust emergency planning.
- Strengthening watershed resilience; coordinating at the basin scale to integrate engineered systems and natural processes for multiple water, agricultural, ecological, and industrial benefits.
- Achieving equity; ensuring all communities, especially those historically underserved, have safe, reliable, and affordable water, and are actively engaged in planning and decision-making.
The plan refreshes the state’s Resource Management Strategies (RMS), expanding emphasis on recycled water and potable reuse, stormwater capture, conjunctive groundwater management, and nature-based solutions (NbS) that restore ecological function while delivering flood protection, water quality improvements, and green community spaces.
Case Studies Across California: Applying the State Framework in Different Contexts
Different case studies across California demonstrate the flexibility of the plan’s framework, illustrating how diverse geographies, governance systems, and community priorities influence implementation. Collectively, they highlight the adaptability of the California Water Plan’s vision to local conditions while maintaining statewide alignment.
Los Angeles County – County Water Plan (CWP)
Adopted in 2023, the CWP is a countywide roadmap to water resilience by 2045, targeting roughly 600,000 acre-feet per year of new local supplies (about 300,000 AFY from stormwater capture). It centers on four pillars: regional supply reliability, groundwater quality/management, small-system resilience & drinking-water equity, and sediment/wildfire management (Nature-Based Solutions (NbS): advanced through two-year action cycles, cross-agency governance, and public progress tracking). We will unpack the LA County Plan in detail in the next blog post.
Official sources: Final Plan PDF
Orange County – Groundwater Replenishment System (GWRS)
Operated by the Orange County Water District (OCWD) and the Orange County Sanitation District, the GWRS is the world’s largest indirect potable reuse facility. Its 2023 expansion boosted capacity to 130 million gallons per day, meeting the needs of nearly one million people. The project reduces reliance on imported supplies while protecting groundwater resources. OCWD’s public tours and outreach programs have built strong community trust in potable reuse—a critical element for statewide adoption.
Official sources: GWRS program page (OCWD)
San Diego – Pure Water San Diego
This multi-phase program integrates direct potable reuse (DPR) and indirect potable reuse (IPR) to supply nearly 50% of the city’s demand by 2035. By diversifying supplies and reducing reliance on imported water, San Diego is enhancing drought resilience. Early, sustained community engagement helped overcome initial skepticism, turning Pure Water into a publicly supported infrastructure priority.
Official source: Program page
Santa Clara Valley Water – Purified Water Program
Aiming to meet at least 10% of demand by 2035, Santa Clara Valley Water’s program combines advanced water purification with public education at its Advanced Water Purification Center. The facility supports Sustainable Groundwater Management Act (SGMA) goals through aquifer recharge while demystifying treatment processes for residents.
Official source: Recycled & Purified Water overview
Sacramento (RegionalSan) – Harvest Water Project
This ag-urban reuse project will deliver 50,000 acre-feet annually of tertiary-treated recycled water for farm irrigation and habitat restoration. By reducing groundwater pumping and nutrient runoff, it supports both supply reliability and ecosystem health. Its integration of wildlife habitat corridors makes it a model for multi-benefit design.
Official source: Harvest Water (Regional San)
Santa Ana Watershed (SAWPA) – One Water One Watershed (OWOW)
SAWPA’s program coordinates multi-county efforts to improve flood management, restore habitat, and protect water quality. Innovative tools for watershed budgeting and climate adaptation modeling ensure that investments align with long-term basin resilience, while equity assessments ensure benefits reach disadvantaged communities.
Official source: OWOW program page
Russian River Watershed – Forecast-Informed Reservoir Operation (FIRO)
By using advanced weather and hydrologic forecasts to guide real-time reservoir operations, FIRO increases reservoir water storage for drought resilience while maintaining flood protection. Its success at Lake Mendocino has led to expansion across the entire Russian River system, including Lake Sonoma.
Official sources: FIRO (Sonoma Water)
Case Studies at a Glance
These seven case studies illustrate how regions across the state are operationalizing the California Water Plan Update 2023 in diverse hydrologic, demographic, and governance contexts. Table 1 summarizes each case study’s primary focus area, its contribution to CWP-2023 goals, and notable innovations or transferable features.
Table 1. Summary of California Water Plan 2023 Case Studies: Focus Areas, Contributions, and Innovations
Case Study Location / Program |
Primary Focus Area |
Key Contributions to CWP-2023 Goals |
Notable Features & Innovations |
|
Los Angeles County Water Plan |
Integrated County Plan |
Aligns local targets with state resilience, equity, and watershed priorities |
Four specialized task forces; measurable 2045 supply goal; strong governance model |
|
Orange County – GWRS |
Recycled Water / IPR |
Increases local groundwater supply; reduces imported water dependence |
World’s largest IPR facility; 130 MGD capacity; robust public tour program |
|
San Diego – Pure Water |
Recycled Water / DPR |
Builds drought-proof local supply meeting ~50% of demand by 2035 |
Multi-phase, linked infrastructure projects; extensive early public outreach |
|
Santa Clara Valley Water – Purified Water Program |
Recycled Water / IPR |
Expands local supply to meet ≥10% of demand; supports SGMA goals |
Advanced Water Purification Center doubles as public education hub |
|
Sacramento – Harvest Water |
Ag-Urban Reuse |
Delivers up to 50,000 AFY recycled water for ag irrigation & habitat |
Reduces groundwater overdraft; integrates wildlife corridor restoration |
|
Santa Ana Watershed – SAWPA OWOW |
Integrated Watershed Management |
Aligns multi-county IRWM actions with state resilience goals |
Watershed budgeting tools; climate adaptation modeling; equity-focused assessments |
|
Russian River Watershed – FIRO |
Climate Resilience & Adaptive Operations |
Improves drought and flood preparedness using forecast-based tools |
Nation’s first FIRO pilot; advanced atmospheric river forecasting; expansion from Lake Mendocino to the full Russian River system |
Benefits, Challenges, and Opportunities
The benefits of early alignment with CWP-2023 are clear. Counties and agencies position themselves for competitive grant funding, reduce policy conflicts between state and local objectives, and create integrated project portfolios that deliver multiple benefits: water supply, quality, flood protection, habitat restoration, and recreation.
However, challenges remain. Sustaining funding beyond initial phases is a common issue, especially for smaller agencies. Technical and financial capacity gaps persist in small and rural water systems, and integration of wildfire-related water risks into supply reliability frameworks is uneven. Public trust in advanced treatment processes and nature-based approaches must be cultivated through ongoing engagement and transparent performance reporting.
Pathways Forward: Advancing the California Water Plan at the County Level
The California Water Plan 2023 (CWP-2023) sets out a statewide vision for a resilient, equitable, and sustainable water future. While key state-led initiatives are already underway, its full impact will be realized only if counties and local agencies actively align their planning and implementation efforts with its objectives.
Current State of Implementation
Since the release of CWP-2023 in April 2024, the Department of Water Resources (DWR) has launched the Watershed Resilience Initiative, funding pilot projects, providing technical assistance, and supporting basin-scale collaborations. Major regulatory progress includes adoption of DPR regulations, removing a barrier to potable reuse, and targeted support for managed aquifer recharge programs.
Pathways for Counties yet to Integrate CWP-2023
Counties can start by crosswalking their local plans including Urban Water Management Plans, Integrated Regional Water Management Plans, SGMA Groundwater Sustainability Plans, and hazard mitigation plans against CWP-2023 objectives. This identifies overlaps, gaps, and opportunities, especially in climate resilience, equity, and supply diversification.
Once aligned, setting measurable local targets ensures accountability. Establishing inclusive task forces, allows for targeted expertise and community engagement. Early action through pilot projects including potable reuse systems, stormwater retrofits, NbS installations, and small system support builds public trust and demonstrates feasibility.
Institutionalizing public engagement is essential: public dashboards, facility tours, and regular CWP-aligned progress reports maintain visibility and accountability.
Next Steps at the State and Local Levels
At the state level, the Department of Water Resources (DWR) is positioned to deepen the implementation of CWP-2023 through expanded technical assistance programs, targeted funding for multi-benefit and equity-focused projects, and continued development of statewide performance dashboards. Priority actions include providing guidance on permitting and regulatory pathways for managed aquifer recharge, offering standardized NbS evaluation metrics, and fostering coordination with federal programs like the Bureau of Reclamation’s WaterSMART grants (DWR, 2024b).
At the local level, counties can leverage success by:
- Applying for Watershed Resilience Initiative funding to replicate governance structures and accelerate priority projects.
- Using the newly adopted Direct Potable Reuse (DPR) regulations to expand water recycling capacity.
- Integrating CWP-2023 objectives into SB 552 drought planning and hazard mitigation plans, ensuring resilience is embedded across policy domains.
- Utilizing state-developed permitting portals to expedite groundwater recharge projects and NbS installations.
By adopting these steps, counties can transition from planning to implementation faster, ensuring that the CWP-2023 framework translates into tangible community benefits within this decade.
Conclusion
The California Water Plan Update 2023 provides more than a policy blueprint—it offers a unifying, adaptive framework that counties can tailor to their unique hydrologic, social, and governance contexts.
The case studies from across California demonstrate the adaptability of the CWP-2023 vision. They show that multi-benefit, equity-centered water management is not only possible but replicable when supported by strong interagency partnerships and sustained community engagement.
As climate pressures intensify, counties that proactively align their strategies with the CWP-2023 framework will not only secure their own water futures but also set a precedent for integrated, equitable water governance across California. The challenge is significant, but the roadmap is clear—and with different models and projects along California leading the way, the state is well-positioned to meet it (DWR, 2023b).
REFERENCES
1. Armitage, D., Berkes, F., & Doubleday, N. (Eds.). (2009). Adaptive co-management: Collaboration, learning, and multi-level governance. UBC Press.
2. Arnstein, S. R. (1969). A ladder of citizen participation. Journal of the American Institute of Planners, 35(4), 216–224. https://doi.org/10.1080/01944366908977225
3. Balazs, C. L., & Ray, I. (2014). The drinking water disparities framework: On the origins and persistence of inequities in exposure. American Journal of Public Health, 104(4), 603–611. https://doi.org/10.2105/AJPH.2013.301664
4. Brown, R. R., Keath, N., & Wong, T. H. F. (2015). Transitioning to water sensitive cities: Historical, current and future transition states. Technological Forecasting and Social Change, 79(4), 598–611. https://doi.org/10.1016/j.techfore.2011.08.006
5. California Department of Water Resources (DWR). (2023a). California Water Plan Update 2023 (Final). California Natural Resources Agency. https://water.ca.gov
6. California Department of Water Resources (DWR). (2023b). California Water Plan Update 2023 – Executive Summary. California Natural Resources Agency. https://water.ca.gov
7. California Department of Water Resources (DWR). (2024a). Small water systems technical assistance program. https://water.ca.gov
8. California Department of Water Resources (DWR). (2024b). Watershed Resilience Initiative. https://water.ca.gov
9. California Water Commission. (n.d.). Harvest Water Program—WSIP Project Review Portal. https://cwc.ca.gov/Water-Storage/WSIP-Project-Review-Portal/All-Projects/Harvest-Water-Program
10. City of San Diego Public Utilities Department. (2024). Pure Water San Diego (program page & media kit). https://www.sandiego.gov/public-utilities/sustainability/pure-water-sd
11. Council for Watershed Health. (2024). Annual progress report: Los Angeles County Water Plan. https://watershedhealth.org
12. Cosens, B. A., & Gunderson, L. (2018). Practical panarchy for adaptive water governance: Linking law to social-ecological resilience. Ecology and Society, 23(1), 30. https://doi.org/10.5751/ES-08831-230130
13. County of Los Angeles. (2024). Implementation of the Los Angeles County Water Plan—Board Motion of December 5, 2023 (Report). https://file.lacounty.gov/SDSInter/bos/bc/1162300_BoardMotion12.05.2023Item8-ImplementationofLACWP_2024.06.10.pdf
14. Dettinger, M. D. (2011). Climate change, atmospheric rivers, and floods in California—A multimodel analysis of storm frequency and magnitude changes. Journal of the American Water Resources Association, 47(3), 514–523. https://doi.org/10.1111/j.1752-1688.2011.00546.x
15. Eckart, K., McPhee, Z., & Bolisetti, T. (2017). Performance and implementation of low impact development—A review. Science of the Total Environment, 607–608, 413–432. https://doi.org/10.1016/j.scitotenv.2017.06.254
16. Emerson, K., & Nabatchi, T. (2015). Collaborative governance regimes. Georgetown University Press.
17. Feinstein, L., Phurisamban, R., Ford, A., & Sellers, S. (2017). Drought and equity in California. Pacific Institute. https://pacinst.org
18. Huitema, D., Mostert, E., Egas, W., Moellenkamp, S., Pahl-Wostl, C., & Yalcin, R. (2009). Adaptive water governance: Assessing the institutional prescriptions of adaptive (co-)management from a governance perspective and defining a research agenda. Ecology and Society, 14(1), 26. https://doi.org/10.5751/ES-02827-140126
19. Koop, S. H. A., & van Leeuwen, C. J. (2017). The challenges of water, waste and climate change in cities. Environment, Development and Sustainability, 19, 385–418. https://doi.org/10.1007/s10668-016-9760-4
20. Los Angeles County Public Works (LACPW). (2024a). Needs assessment summary: Los Angeles County Water Plan. https://dpw.lacounty.gov
21. Los Angeles County Public Works (LACPW). (2024b). LA County Water Plan: Governance and stakeholder engagement. https://dpw.lacounty.gov
22. Los Angeles County Water Plan Team. (2023). Los Angeles County Water Plan—Final. https://lacountywaterplan.org/assets/pdf/Final%20CWP/LA-County-WaterPlan_Final.pdf
23. Metropolitan Water District of Southern California. (2024). Integrated resource plan update. https://mwdh2o.com
24. OC San (Orange County Sanitation District). (2023). The Groundwater Replenishment System final expansion (news release). https://www.ocsan.gov/news/the-groundwater-replenishment-system-final-expansion/
25. OCWD (Orange County Water District). (n.d.). Groundwater Replenishment System (GWRS) (program page). https://www.ocwd.com/gwrs/
26. Olmstead, S. M. (2010). The economics of water quality. Review of Environmental Economics and Policy, 4(1), 44–62. https://doi.org/10.1093/reep/rep016
27. Ostrom, E. (2009). A general framework for analyzing sustainability of social-ecological systems. Science, 325(5939), 419–422. https://doi.org/10.1126/science.1172133
28. Regional San. (n.d.). Harvest Water (program site). https://www.sacsewer.com/harvest-water/
29. SAWPA (Santa Ana Watershed Project Authority). (2018). OWOW Plan Update 2018 (IRWM plan hub). https://sawpa.gov/owow/owow-irwm-plans/owow-plan-update-2018/
30. SAWPA (Santa Ana Watershed Project Authority). (n.d.). OWOW—One Water One Watershed (program page). https://sawpa.gov/owow/
31. Sonoma Water. (n.d.). Forecast-Informed Reservoir Operations (FIRO) (program page). https://www.sonomawater.org/firo
32. UC San Diego, Center for Western Weather and Water Extremes (CW3E). (n.d.). FIRO—Lake Mendocino (program brief). https://cw3e.ucsd.edu/firo_lake_mendocino/
33. UNESCO. (2019). The United Nations World Water Development Report 2019: Leaving no one behind. UNESCO Publishing. https://unesdoc.unesco.org
34. U.S. Bureau of Reclamation. (2022). Title XVI—Sacramento Regional County Sanitation District (authorized application brief). https://www.usbr.gov/watersmart/title/docs/applications/authorized/2022/TitleXVI-Sacramento-Regional-County-Sanitation-District-508.pdf
35. Valley Water (Santa Clara Valley Water District). (n.d.). Purified Water Project—Ensuring a reliable water supply (project page). https://www.valleywater.org/project-updates/purified-water-project-ensuring-reliable-water-supply
36. Valley Water (Santa Clara Valley Water District). (n.d.). Recycled and purified water (program overview). https://www.valleywater.org/your-water/recycled-and-purified-water
