AI Data Centers Spark San Jose Water Concerns

San Jose is adding data-center projects as city officials court AI-related growth, while researchers and residents press for clearer accounting of how those facilities will use water and power. A May 18 report by San Jose Spotlight said more than a dozen data-center projects are taking shape in Santa Clara County, where local leaders have said environmental impacts will be reviewed before facilities begin operating. Researchers from Santa Clara University and the policy group Next 10 said the current review system leaves major gaps on water use, especially in a drought-prone state. Residents have also raised concerns in recent city debates over whether projects should move ahead before more protections are in place. ### Which projects are at the center of the San Jose debate? San Jose’s own environmental review page lists a proposed 396,914-square-foot data center at 1657 Alviso-Milpitas Road near an existing power plant and wastewater treatment facility. The city page says the project would include two single-story data-center buildings and a maximum electrical load of 99 megawatts, with an estimated load of 77 megawatts. The same filing says the project also includes 224 renewable natural gas generators rated at 0.45 megawatts each, plus diesel-powered backup equipment. (localnewsmatters.org) An April 26 Local News Matters report described another San Jose proposal at 323 Terraine St. that would combine an 18-story apartment building with an 11-story data center and a 10-story parking garage. That project became a focal point for residents who said the city should weigh environmental effects before approving more facilities. (sanjoseca.gov) ### Why are researchers focused on water rather than just electricity? A May 2026 report from Santa Clara University and Next 10 examined data centers across California through the lens of water availability and environmental justice. The report said many data centers use water to cool equipment, but water demand varies widely by facility and can range from almost none to the equivalent of thousands of households, depending on cooling design. (localnewsmatters.org) Iris Stewart-Frey, a professor of environmental science at Santa Clara University, told San Jose Spotlight that the concentration of AI data centers has increased pressure on water planners to understand what they are approving. San Jose Spotlight reported that the researchers found legal requirements for environmental review to be uneven, making it hard to estimate cumulative effects on local water systems. (next10.org) ### What information do researchers say is missing? The Next 10 and Santa Clara University report said researchers contacted every water provider in districts where data centers are located and did not receive data on water use for individual developments or cumulative project demand. CalMatters reported the same study found that, even when projects undergo more detailed environmental review, public documents often omit basic details such as the owner or operator, facility size, cooling type, water source and whether the supply is recycled or potable. (sanjosespotlight.com) CapRadio reported that lax disclosure rules have left the public without a clear picture of actual water consumption as data centers expand into water-stressed California communities. Berkeley Law’s Center for Law, Energy and the Environment published a February 2026 report focused on regulating data-center water use in California, adding to the push for clearer statewide standards. (sanjosespotlight.com) ### How is San Jose encouraging more data-center development at the same time? Mayor Matt Mahan and PG&E announced a partnership on July 25, 2025 aimed at attracting large power users, including data centers, to San Jose. KQED reported the agreement was designed to give developers more certainty that electricity would be available for 10 large data-center and industrial projects in the city’s north, south and downtown areas. (capradio.org) City officials told KQED that each data center could generate about $3.4 million to $6.8 million in annual city revenue through utility and property taxes. Mahan said the city wanted to offer “speed and certainty” to developers and keep data centers in Silicon Valley. ### What happens next in San Jose? The City of San José environmental review page says the Planning Commission held a public hearing on the Alviso-Milpitas Road project on March 26, 2025, and additional project documents are posted through the city and California Energy Commission dockets. (kqed.org) The broader policy debate is also moving beyond one site: researchers have called for stronger environmental review requirements and clearer reporting on cooling systems and water demand as more projects are proposed across Santa Clara County. (sanjoseca.gov)