South Bay AI data center water concerns

San Jose is considering a new wave of data-center development as city officials and utilities prepare for large new electricity demand, while researchers and residents say basic facts about water use remain hard to obtain. A May 14 report from Next 10, authored by researchers at Santa Clara University, said California’s expanding data-center footprint is increasingly intersecting with water-stressed and socially vulnerable communities. In Santa Clara County, the researchers said, more than a dozen projects are taking shape even as public agencies and developers disclose little about cooling systems and actual water consumption. Local advocates have responded by pressing for stronger environmental review and enforceable reporting before additional projects move ahead. ### Why are water questions surfacing now? The May 14 Next 10 report said large-scale data centers are increasingly being sited in parts of California already facing constrained water supplies due to climate change. San Jose and the broader South Bay are not described in the report as the state’s most water-stressed region, but the researchers said the area’s concentration of projects makes cumulative impacts harder to judge when disclosure is limited. (sanjosespotlight.com) Iris Stewart-Frey, a professor of environmental science at Santa Clara University, told San José Spotlight that the “accelerated concentration” of AI data centers has increased pressure on water planners to understand what they are facing. The same report found that researchers who contacted water providers in districts with data centers did not obtain facility-level or cumulative water-use data for those developments. (next10.org) ### What does San Jose itself have on the table? San Jose’s own environmental-review portal lists an active Environmental Impact Report for a project identified as “San Jose Data Center,” file numbers CP23-016 and ER20-219. The city says that project would include two single-story data-center buildings totaling about 396,914 square feet near an existing power plant and wastewater treatment facility at 1657 Alviso-Milpitas Road. (sanjosespotlight.com) City records say that same project would have a maximum electrical load of 99 megawatts, with an estimated load of 77 megawatts. The filing also says the project includes 224 renewable natural gas generators rated at 0.45 megawatts each, plus two Tier 4 diesel-powered administrative generators and a 1.5-megawatt standby generator. (sanjoseca.gov) ### What is still unclear in the public record? The public documents reviewed for this story describe the project footprint, electrical load and backup generation, but they do not spell out an easily accessible project-specific water-use figure in the summary materials surfaced on the city pages. The broader concern raised by researchers is that this gap is common across California, where cooling technology and water demand can vary sharply from one facility to another. (sanjoseca.gov) Many data centers use water to cool servers, while others use systems that consume far less water, according to the Santa Clara University researchers. Without facility-specific reporting, Stewart-Frey and other researchers said, planners and nearby residents are left estimating impacts rather than measuring them directly. ### How does power demand fit into the fight? (sanjoseca.gov) On July 25, 2025, San Jose and PG&E announced an implementation agreement tied to rising demand from data centers and other large energy users. The city said PG&E had requests for nearly 2,000 megawatts of new data-center demand in the San Jose area and that the agreement set performance milestones for grid upgrades. Mayor Matt Mahan said at the time that San Jose was ready to support AI-related growth, while PG&E said the agreement was intended to speed power delivery. (sanjosespotlight.com) For critics of rapid buildout, that power planning has sharpened questions about whether water, air quality and backup-generator impacts are being examined with the same level of specificity. That concern is reflected in local coverage of recent council and planning discussions, where residents asked for tighter review of environmental effects before approvals multiply. (sanjoseca.gov) ### What are researchers and advocates asking for? Next 10’s May 14 publication calls for stronger environmental review and more consistent disclosure as California adds data centers. The Santa Clara University researchers said current legal requirements are too uneven to predict the water effects of the state’s fast-growing buildout. A separate February 2026 policy report from UC Berkeley Law’s Center for Law, Energy and the Environment said California is examining possible regulatory responses to data-center water use. (sanjoseca.gov) That report described data-center water consumption as an environmental issue that current policy frameworks are still catching up to address. ### Where does the issue go next? (next10.org) San Jose’s environmental-review page says project documents for the Alviso-Milpitas Road data center remain available through the city and the California Energy Commission docket. The city page also lists Planning Commission hearing dates from March 2025 for the current addendum process, and future permitting and environmental-review updates would appear through those same city channels. (law.berkeley.edu) The next public test is likely to come in those filings: whether city, utility and developer documents begin to include project-level water data, cooling details and enforceable conditions that residents and researchers have said are missing. (sanjoseca.gov) (sanjoseca.gov)