California's explosive data center expansion is creating a hidden water crisis that regulators aren't monitoring. The state is on track to have more than 300 data centers operating by 2030, with 24 major new facilities under development. Yet California doesn't require these facilities to report how much water they use, leaving residents, local officials, and even water districts in the dark about the infrastructure strain they'll face.

The scale of the problem is staggering. A single large data center proposed for Imperial Valley, about 115 miles east of San Diego, would consume 750,000 gallons of water per day to cool its servers. That's equivalent to the daily water use of roughly 10,000 households. The facility, expected to be completed by 2028, would span 17 football fields and cost approximately $10 billion to build.

Why Is Water Consumption Such a Big Deal for Data Centers?

Data centers generate enormous amounts of heat as they process information. To keep servers from overheating, most facilities rely on water-based cooling systems. The hotter the climate, the more water a facility needs. During peak summer days, a 100-megawatt data center can use about 1 million gallons of water for evaporative cooling, according to research from the University of California, Riverside.

The problem isn't just the volume of water consumed. It's the timing and location. More than 90 percent of data centers in the United States draw their cooling water from municipal water systems, the same sources that serve homes and farms. When a large facility comes online in a water-stressed region, it can create bottlenecks in local water infrastructure, even if the annual water consumption seems manageable when spread across the entire state.

"Only comparing the annual totals can obscure the real water challenge," explained Shaolei Ren, an associate professor of electrical and computer engineering at the University of California, Riverside.

Shaolei Ren, Associate Professor of Electrical and Computer Engineering, University of California, Riverside

What Are the Infrastructure Costs California Faces?

Building new water infrastructure takes time. While a data center can be constructed in two to three years, developing new water sources can take as long as 20 years. This mismatch creates a critical challenge for California, which is already grappling with a deepening megadrought and declining Colorado River flows.

Research from UC Riverside estimates that water infrastructure upgrades across the United States could cost between $10 billion and $58 billion to support data center expansion through 2030. For California alone, just the 24 data centers planned for completion by 2030 could require $200 million to $800 million in water infrastructure upgrades, depending on where they're built and how efficiently they operate.

The financial burden falls on local communities. Residents worry that water and electricity rates will rise once new data centers begin operating. In Imperial Valley, where the massive proposed facility would be located, community members have organized opposition, displaying "Not In My Backyard" signs and raising concerns about long-term utility costs.

How Can Communities Address Data Center Water Demands?

• Alternative Water Sources: Some data centers are exploring treated wastewater or graywater for cooling instead of drawing from municipal drinking water supplies, which could reduce strain on local water systems.
• Transparency Requirements: California could mandate that data centers report their water usage to the state, similar to how other industries track consumption. Recent efforts to require such reporting have stalled, but advocates continue pushing for legislation.
• Regional Planning: Coordinating data center placement with water availability and renewable energy resources could help distribute the infrastructure burden more equitably across the state.

Public concern about data center impacts is growing. A nationwide poll by the US Water Alliance found that 54 percent of respondents are extremely or very concerned about the effects data centers will have on water quality, water supply, and costs in their area. Two-thirds of voters said it's important for their state to have a plan for managing data center water impacts.

"I suspect that as data centers continue to be part of the broad conversation, then these numbers will probably continue to go up as people are more concerned about the impacts they have on the things that affect them and their communities, like supply, quality and cost," said Scott Berry, senior advisor on policy and external affairs at the US Water Alliance.

Scott Berry, Senior Advisor on Policy and External Affairs, US Water Alliance

How Does California's Data Center Boom Compare to Other Water Users?

While data centers are a growing concern, they're not yet the largest water consumer in California. Alfalfa irrigation in the Imperial Valley alone uses more than 800 billion gallons per year, far exceeding current data center consumption. The beverage industry uses 533 billion gallons annually, and the semiconductor industry uses 59 billion gallons.

However, the rapid growth trajectory of data centers makes them a unique challenge. Current estimates suggest data centers use about 39 billion gallons of water nationally each year. But as artificial intelligence adoption accelerates, that number is expected to climb sharply. The key difference is that data centers can be built quickly in concentrated locations, whereas traditional agricultural and industrial water use is spread across larger geographic areas.

California's lack of a central permitting authority for data centers complicates planning efforts. Most facilities are overseen by individual city and county governments, making it difficult to coordinate regional water management strategies. The California Public Utilities Commission notes that 286 data centers are currently operating in California, with more on the way.

The state trails only Virginia and Texas in the number of individual data center locations, but California's centers have much lower total new electricity capacity, which may indicate lower water demand than facilities in other states. Still, the rapid expansion means California will need to develop a comprehensive strategy for managing water resources alongside its digital economy growth.