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,…