Data centers power the modern internet, storing and processing the data required for our online activities. Though these types of server facilities have existed for decades, they are popping up in greater numbers and at a larger scale than ever before to support artificial intelligence technology, which demands more computing resources.
At their simplest, data centers are made up of many computer servers, typically stacked in racks and lined up in rows within a large building. When those servers run, they generate heat. And to keep running efficiently, they must be cooled. Most data center cooling systems today achieve this cooling with large volumes of water.
Despite their intensive water use, tech companies continue to site data centers in arid areas. About two-thirds of data centers constructed since 2022 are located in areas of high water stress, with 70% of facilities concentrated in just five states (including California). California currently has over 300 data centers, with many more planned. But regulatory gaps allow data center operators in California to use inefficient cooling technology, and to operate without disclosing how much water their facilities use.
Lawmakers across the nation are seeking to address the environmental impacts of data centers. In 2025, at least eight states, including California, saw proposed legislation which would require data centers to report their water use.
Last year, Governor Newsom vetoed Assembly Bill 93, authored by Diane Papan. This bill would have required data centers to report their expected water use prior to applying for business licenses, and to certify their actual annual water use when renewing business licenses. AB 93 would have allowed local governments to make informed decisions about whether to approve data centers by making their water use transparent. This bill would have filled a key need, as there are currently no requirements for data centers in California to disclose how much water they use.
The public and regulators need more information to understand the true impacts of data centers. As a global leader in technology, California should model how this can be done. For these reasons, CCKA will push to revisit the transparency goals of AB 93.
In addition to a lack of reporting requirements, there are no requirements in California that data centers use water-efficient cooling technology. Which cooling method(s) data centers choose to use greatly impacts how much water they use. Often, data centers rely on potable water to cool servers, and they consume water instead of reusing it.
Many data centers currently use evaporative cooling towers, which consume substantial volumes of water. In this type of system, warm air is drawn through pads saturated with (typically potable) water. About 80% of water is lost to evaporation, while the remaining 20% is discharged to a wastewater treatment facility. When this cooling method is used, water is rarely reused onsite.
Next year, when California hopefully has a governor who understands the importance of regulating data centers rather than prioritize his own “tech-bro” image for a presidential campaign, CCKA will push for an efficiency technological standard for data centers. Setting such a standard will allow data center operators to adopt more efficient cooling methods as appropriate for individual facilities but will hold the industry accountable in its water use, ensuring that the use of AI technology does not come at the expense of nearby municipal users or the watershed.
Policy Manager Madi Richards advances statewide policies that protect water quality and access to clean water throughout California
