Data Centers and Santa Clara County's Water Supply

July 15, 2026

Outside of a data center in Silicon Valley

As new data center projects are being considered in Santa Clara County, many people have questions about how data centers use water and what this could mean for the area's water supply.

Data centers use cooling systems to manage the heat created by their equipment. Depending on the system, cooling may use water through evaporative or liquid cooling. Some data centers use air cooling, which does not require the use of water but uses more energy. Based on information available to Valley Water, many proposed facilities in Santa Clara County plan to use water-efficient cooling technologies or recycled water where available.

Santa Clara County is home to about 91 data centers, most of which are in Santa Clara and San José. Additional facilities are being considered in Santa Clara, San José, and Gilroy.

One of the most common questions Valley Water receives is how much water data centers use. We do not have exact water-use figures or numbers for individual data centers because we supply water to local water retailers, not directly to homes or businesses. To Valley Water's knowledge, water retailers do not track data centers as a separate customer category, so this information is not available.

For Valley Water's water supply planning purposes, data centers are included in the larger Commercial, Industrial, and Institutional (CII) customer category. This category accounts for about 26% of all water used in Santa Clara County. Overall water use in the county has declined over the past 20 years because of water conservation and more water-efficient technologies.

Valley Water supports water conservation by helping businesses save water. The Water Efficient Technology (WET) Rebate Program offers rebates of up to $100,000 for eligible water-saving projects. Valley Water also supports recycled water projects, including the Silicon Valley Advanced Purification Center and expanded recycled water systems in South County.

Valley Water has been following the development of data centers in Santa Clara County and elsewhere. As more information becomes available, Valley Water will include future data center water use in our planning efforts to support a sustainable water future for Santa Clara County.

Valley Water manages an integrated water resources system that includes the supply of clean, safe water, flood protection and stewardship of streams on behalf of Santa Clara County's 2 million residents. Valley Water effectively manages 10 dams and surface water reservoirs, three water treatment plants, an advanced recycled water purification center, a state-of-the-art water quality laboratory, nearly 280 acres of groundwater recharge ponds and 350 miles of waterways. We provide wholesale water and groundwater management services to local municipalities and private water retailers who deliver drinking water directly to homes and businesses in Santa Clara County.