Data centers have been in California for a long time, and the number and size of facilities are growing to support the rapid boom of artificial intelligence. Oversight, though, has not kept pace with development. In particular, from a water supply perspective, we do not know how much water data centers are using to cool their operations.
The Problem: Growing Water Usage & Location Concerns
While data centers’ water consumption may currently represent a small portion of the state’s water demand as a whole, it is growing rapidly – nearly doubling from 2019 to 2023 – with near-future demand expected to rise up to 4.6 times greater than 2019 levels.[1] Unlike other industries, data centers also primarily rely on potable water for on-site use.
The total volume of a facility’s water use is far from the only relevant factor in determining its water-related impact. “Hyperscale” facilities in California are disproportionately sited in low-income communities and areas with greater water scarcity, compounding existing risks to vulnerable California residents.[2] Meaningfully assessing the impact of a data center’s water use requires viewing that use in a local context.
A Lack of Transparency
California currently does not require data centers to report on their water use. The total amount of water used, proportion of direct to indirect use, and water source(s) remain opaque for many facilities. Often, data centers do not undergo full environmental review, and what environmental data may be available is voluntarily reported by project operators in corporate sustainability reports. Globally, less than half of companies that own or operate data centers collect data on water usage for corporate sustainability purposes.[3]
The amount of water used by data centers varies greatly based on a number of factors, including the site’s climate, the source of energy generation, the type of cooling technology employed, and whether the facility recycles water. Several legislative proposals have been introduced to help local governmental entities and the public better understand how much water data centers use and for what purposes.
Last year, Governor Newsom vetoed Assembly Bill 93, authored by Diane Papan, which 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.
Looking Ahead
This year, several bills address the environmental impacts of data centers, including two that directly relate to data centers’ water use: Assembly Bills 2469 and 2619, both authored by Diane Papan.
AB 2469 (Data centers: water use disclosures) would require data center project applicants to provide information on water use and assume infrastructure costs as conditions of project approval; place guardrails on data center siting; and create a new commercial, industrial, and institutional (CII) classification for large consumptive use facilities, including data centers. It would prohibit the construction or expansion of a data center within a groundwater basin designated as “critically overdrafted” unless an assessment shows the project does not pose a disproportionate risk to an environmental justice community.
AB 2619 (Water resources: data centers) would require owners or operators of data centers to provide information about water use to cities and counties and develop state guidance to support local decision-making. Similarly to last year’s vetoed bill, the bill would require data center owners or operators to provide information about the facility’s water use both before and when applying for a business license. It would also integrate data centers into Urban Water Management Plans for holistic and water supplier-specific supply and demand assessments.
The Bottom Line
Maintaining California’s status as both a technological and environmental leader requires policies that increase transparency and efficiency surrounding data centers’ water use. Standardized water data availability will allow local decision-makers and the public to make context-specific assessments of the potential risks and benefits of planned data centers, ensuring they do not come at the expense of communities and the environment.
[1] F. Noel Perry et al., An Assessment of CA Data Centers’ Environmental and Public Health Impacts (2025).
[2] Stewart-Frey et al., The Intersection of Data Center Development, Water Availability, and Environmental Justice in California (2026).
[3] Uptime Intelligence, Uptime Institute Global Data Center Survey (2025).
Policy Manager Madi Richards advances statewide policies that protect water quality and access to clean water throughout California
