Why are C-WIN and the Central Delta Water Agency Suing the Department of Water Resources?
On October 8, 2026, the California Water Impact Network (C-WIN) and the Central Delta Water Agency (CDWA) filed a lawsuit against the California Department of Water Resources (DWR) for harm caused by DWR’s operation of the State Water Project (SWP). Below are FAQs about the lawsuit.
Why was the lawsuit filed against DWR?
The Department of Water Resources is the owner and operator of the SWP, which pumps an average of over 2.2 million acre-feet of water (729 billion gallons) out of the Delta for agriculture and urban use in Silicon Valley, the San Joaquin Valley, and Southern California. However, DWR’s contracts for SWP water total over 4.17 million acre-feet, and DWR and its contractors continue to lobby for additional SWP exports. Up until 2000, DWR pushed plans to take 5 million acre-feet from California’s North Coast rivers. Since then, DWR has developed various approaches to augment its SWP pumping capacity. The current plan, called the Delta Conveyance Project, would construct additional SWP pumps and a massive tunnel to take more water out of the Sacramento River above the Delta, at a cost of $60-$100 billion.
As a state agency, DWR has a duty to protect public trust resources, such as fish, other aquatic species, and the ecosystems that support them. However, DWR’s operation of the SWP has contributed to the ecological decline of the Delta, including the near extinction of multiple fish species, with concomitant harms to Delta farmers served by CDWA. Our lawsuit argues that DWR is failing to uphold its public trust duty, which exists independent of other legal and regulatory requirements. We are also claiming that DWR, as the operator of the SWP, is wasting, unreasonably using, and unreasonably diverting water from the Delta in violation of the state constitution. In addition, our lawsuit maintains that DWR’s diversions must be limited to reasonable amounts that allow for the Delta ecosystem and Delta water users to survive and thrive.
What are the main claims in the lawsuit?
The main claims are that DWR has violated the Public Trust Doctrine and the prohibition against waste and unreasonable use of water in the California Constitution. The Public Trust Doctrine has existed for centuries, and California courts have cited it as a core duty in water allocation cases. The doctrine requires state government to preserve public trust resources and to avoid or mitigate any harm to trust resources when feasible – a requirement that DWR has consistently ignored. Our argument is that it is feasible for DWR to operate the SWP in a manner that protects public trust resources, and that DWR has not compellingly justified its operations decisions that deplete those resources. Our waste and unreasonable use argument contends that DWR’s Delta unsustainable diversions are wasteful and unreasonable because of the harm they cause to the Delta, its trust resources, and the communities that depend on it, and therefore, that DWR should be required to reduce diversions to reasonable and sustainable levels.
Why did CWIN and CDWA file together?
CWIN and CDWA are united in the goals of restoring Delta ecosystem function and improving Delta water quality for the benefit of all water users. Each organization has filed legal challenges over the years, attempting to slow and ultimately reverse the decline of the Delta due to excessive diversions. This lawsuit is a joint effort to achieve durable legal remedies to avert total collapse of the largest estuary on the West Coast of the Americas.
What is the lawsuit aiming to achieve?
We are seeking an outcome that ensures more fresh water flows into and through the Delta. Additional flow is the most important element for fish survival and for the continued viability of Delta farming. The lawsuit seeks to achieve this outcome by establishing that excessive water diversions from the Delta are violations of the Public Trust Doctrine and unreasonable due to their devastating impacts on the Delta ecosystem and community. This finding, along with a court enforcement order to reduce diversions to reasonable levels, would blunt the political influence that has for decades prioritized revenues and profits for Southern California and San Joaquin Valley water districts over all other communities, industries, and the environment.
How does the lawsuit relate to the Bay-Delta Plan?
The Bay-Delta Plan is supposed to create rules to protect water quality in the Bay-Delta watershed. However, it has been rendered ineffective by the same powerful interests – e.g., Central Valley corporate growers and large Southern California developers – who have opposed our efforts to protect the Delta. DWR has used the Bay-Delta Plan as justification for shirking its public trust duties. Our lawsuit argues that DWR has an independent duty to protect the public trust and prevent waste and unreasonable use of water in its operation of the SWP.
How is this lawsuit different from previous water litigation?
Most previous litigation has focused on compliance with specific statutes, such as the California Environmental Quality Act and the state and federal Endangered Species Acts. Although claims have occasionally produced victories, they have not stopped the Delta’s ecological decline. Our lawsuit is seeking a comprehensive solution based on higher law – the state constitution and the public trust doctrine. We think it is past time for DWR to fully comply with these fundamental duties, given the deep crisis facing the Delta watershed.
How could this lawsuit impact California’s economy?
California has one of the world’s largest economies and the largest agricultural sector in the United States. This lawsuit would have little impact on the state’s overall economy. However, reducing water available to agriculture and urban water districts would have localized direct costs in reduced revenues. Conversely, leaving more water in the rivers would also produce economic benefits, including sustainable agriculture, recreation, enhanced real estate values and improved commercial fishing. Moreover, urban water districts would accelerate investments in local water supplies, which could generate additional economic benefits.
How could this lawsuit impact water bills?
Many Californians face high water bills due to the variability of supplies and significant operational cost drivers, such as rising electricity rates. As climate change makes our hydrology even more variable, there will be further upward pressure on rates from more extreme droughts and urban-wildland fires. Keeping water bills affordable requires more federal and state investment in reliable and sustainable water sources, such as recycled water, and prioritizing urban water supplies over agricultural profits. If successful, this lawsuit would stop water districts from relying on DWR’s unsustainable excessive diversions from the Delta.
The Newsom administration’s $60-$100 billion proposed Delta Conveyance Project, if built, would drive up bills further. Stopping that project and requiring agriculture to absorb most of the reductions in water diversions would keep water bills from spiking dramatically. Thus, prevailing in this lawsuit would greatly benefit ratepayers.
How could this lawsuit impact water reliability for Silicon Valley and Southern California?
Silicon Valley and Southern California have made great strides in water conservation and local and reliable supply augmentation through water recycling, onsite reuse, and other technologies (e.g., cleaning up contaminated groundwater). Their over-reliance on the State Water Project is preventing further progress because the SWP does not deliver reliable supply – it is severely restricted during droughts. Moreover, both regions would have even greater supply reliability if the state exports prioritized urban use over unsustainable agricultural production. By reducing SWP deliveries, our lawsuit will force regional water suppliers to abandon the expensive and harmful Delta Conveyance Project and focus on building true reliability via local solutions and reduced agricultural export demands.