Assembly committee hears testimony on AB 93, which would require data centers to estimate and report water use

Assemblymember Rebecca Pappan presented AB 93 to the Assembly Local Government Committee on Wednesday, saying the bill would require state and local officials to account for the water needs of data centers as the state plans for housing and other demands.

“Water is one of California’s most precious resources and data centers are thirsty,” Assemblymember Pappan said, arguing that a single midsize data center can use about 300,000 gallons of water per day and larger facilities can use as much as 5,000,000 gallons daily. She said AB 93 directs the Department of Water Resources to develop best management practices for data centers, requires data‑use estimates when businesses apply for local permits or licenses, and requires reporting of actual consumption at renewals.

The committee heard technical testimony and research in support. Shaoda Yuan, an associate professor at UC Riverside, described how many data‑center cooling systems rely on water evaporation and said publicly available data on water consumption is limited. “According to estimated water usage effectiveness in 2023, California data centers consumed about 5,000,000,000 liters of water,” Yuan said, and cited Lawrence Berkeley National Laboratory projections that consumption could double or more by 2028 absent mitigation.

Sean Bothwell, executive director of California Coastkeeper Alliance, endorsed the bill for three reasons: it would (1) bring data centers into conservation programs, (2) require local governments to know estimated water use before issuing business licenses, and (3) require reporting of actual use so utilities can set appropriate rates. “In order to do water rates appropriately, you need to know who the most heavy‑use water users are,” Bothwell said, adding that high water users can increase costs that fall disproportionately on low‑income ratepayers.

Industry witnesses said they are engaged with the bill but urged caution. Kara Boinder of the Data Center Coalition said cooling choices depend on climate, humidity, availability of recycled or nonpotable water, and other site‑specific factors. “There is no one‑size‑fits‑all solution for cooling and the best approach considers many factors,” Boinder testified, arguing that conditioning business‑license approval or renewal on inflexible requirements could be prohibitive for retrofits and could reveal sensitive technical information.

Representatives of local government and utilities said they appreciate the amendments and want to continue work with the author. Melissa Sparks Kranz of the League of California Cities thanked the author for amendments that she said had moved the bill in the right direction. Julia Hall of the Association of California Water Agencies and Andrea Abrazal of the California Municipal Utilities Association also asked to review amendments and continue discussions.

Committee members asked technical and implementation questions but did not take a formal roll‑call vote on AB 93 during the hearing. Pappan told the committee she would accept the committee’s amendments and asked for an aye vote when the committee later convenes with a quorum.

Why it matters: Data centers are expanding in California to serve AI, cloud and other computing demands. Testimony at the hearing emphasized that, unlike many energy resources, water availability is regionally constrained and often cannot be easily substituted: much of data‑center water use is evaporative and removed from local supplies. Supporters said the bill would give local governments and water agencies the information they need to set rates and plan infrastructure; industry witnesses urged flexibility so that cooling and energy tradeoffs can be managed site by site.

What the bill would do: AB 93 would (per the author’s description and testimony) require the Department of Water Resources to develop best management practices for data centers, require applicants for local business licenses to estimate data‑center water use, require reporting of actual consumption at renewal, and direct state agencies including the State Water Resources Control Board and the California Energy Commission to develop guidance on emerging cooling technologies.

Discussion highlights and unanswered questions: Witnesses and members pressed for clearer definitions of which facilities would be covered, how local governments and utilities would verify reported use, how confidentiality and proprietary technology concerns would be handled, and how the law would treat recycled or nonpotable water and off‑site water used to generate electricity (so‑called offset water). Several witnesses asked for more time to review committee amendments in print.

Next steps: The author accepted committee amendments during her presentation but no formal vote was recorded during the hearing because the committee was operating as a subcommittee at that point. The author asked members to support the bill when the committee next has a quorum.

Sources: Testimony from Assemblymember Rebecca Pappan; Shaoda Yuan, Associate Professor, UC Riverside; Sean Bothwell, California Coastkeeper Alliance; Kara Boinder, Data Center Coalition; League of California Cities; Association of California Water Agencies; California Municipal Utilities Association.