It’s a new year, and the state and federal legislatures are welcoming a slew of fresh faces to their storied halls. As the next crop of public servants finds its footing in Sacramento and Washington DC, now’s the time to take stock of the most important water issues facing California in 2025. And the biggest issue in 2024 will very likely persist in 2025 and beyond: heat.

It’s no secret that temperatures are rising across the globe. Here in California, we’re feeling the impacts in our water system. Climate whiplash—the swing between extreme droughts and extreme floods—is increasing, snowpack is diminishing, and wildfires are growing ever more severe. All of this is impacting the state’s people, farms, ecosystems, and vast water grid, which supplies water to the majority of the state’s nearly 40 million residents.

But Californians are nothing if not innovative and resilient. While Californians have work to do on climate adaptation, we’ve already made real progress in several key areas:

• Urban water use has plateaued since the 1990s, remaining flat even though the population grew by 5.5 million people.
• Groundwater recharge has leapt forward, growing by 17% between 2017 and 2023 and proving the state can get more water into its best storage infrastructure: underground aquifers.
• Better forest management is set to scale up in the coming years thanks to both state and federal commitments to increase controlled burns and mechanical thinning, which will reduce severe wildfires.
• Sea level rise adaptation planning is underway in many coastal jurisdictions, thanks to state legislation and leadership as well as local implementation.

Yet California faces very real challenges which state leaders must grapple with in the coming years—all of which will be exacerbated by the changing climate. Among them:

• Floods. California is prone to rare but extremely damaging floods—and the changing climate is supercharging this risk. (Karla Nemeth, director of the Department of Water Resources, has said that floods are the issue that keeps her up at night.) Lawmakers and agencies can improve risk modeling and reservoir operations, incentivize insurance uptake, and ensure functional warning systems and emergency response and recovery. In the long term, expanding efforts to harness floodwaters can protect communities while recharging depleted aquifers and/or aiding ecosystems.
• Freshwater ecosystems. California is blessed with a remarkable abundance of wildlife species found nowhere else, but studies have shown that over half of our freshwater species are likely to be extinct by the end of this century without major interventions. Decades of water and land use changes have pushed many species to the brink—and the window to save them is closing. Swift, thoughtful action can help us preserve the state’s natural heritage.
• Land use transitions. Reducing groundwater pumping is key for the long-term health of agriculture in the San Joaquin Valley and all over the state, but the transition will be difficult. As efforts to implement the Sustainable Groundwater Management Act accelerate, some 500,000 to 900,000 acres may need to come out of irrigated production in the San Joaquin Valley alone. It will be key to support growers, workers, and residents to prevent harm, ensure access to clean drinking water, mitigate dry wells, and soften the economic blow.

In the coming years, our researchers will focus on ways the state can become even more resilient in the face of climate change, while ensuring equitable outcomes for the lowest-income residents. We’ll be looking at how to better track water use in the state, because you can’t manage what you don’t measure. We’ll also examine how to fund climate adaptation efforts—a tricky issue for the cash-strapped state facing huge adaptation price tags. And we’ll elevate the innovative multi-benefit projects that hold great promise for our struggling ecosystems, farms, and communities.

Our state is rich in resources—and a model to the nation and the world. In some sectors, California is lucky to have years of progress that it can build on. But in other sectors, it will be crucial to address some of the state’s thorniest water issues in efficient and cost-effective ways and with ample cooperation. Commitment to relying on data for decision making will aid all efforts to tackle the big challenges ahead.