California AB 2619 Passes Senate With Data Centre Water Reporting Requirements

California Data Centre Water Reporting Would Start Before Licensing

Before applying for an initial city or county business licence, equivalent instrument or permit, a data centre owner or operator would provide its water supplier with a good-faith estimate under penalty of perjury. The estimate would state expected water use, the anticipated source and projected volumes for the maximum day, maximum month and average year.

The applicant would report the same information on the city or county application. At renewal, it would report annual water use for the preceding calendar year, including total and direct water use, as well as the cooling-system type.

Direct annual water use is defined as water withdrawn, delivered or otherwise used on site for cooling, sanitation, irrigation and other operations. Reporting would identify whether the source is potable, non-potable or recycled water.

The bill covers three size bands. Type I hyperscale facilities have more than 10,000 servers or consume more than 25 megawatts. Type II facilities use at least 2 megawatts and no more than 25 megawatts. Type III facilities use less than 2 megawatts, meaning the proposal is not limited to hyperscale projects.

The Senate Amendment Removed A State Guidance Mandate

Earlier text would have required the Department of Water Resources and California Energy Commission to produce water-efficiency guidelines and best practices by 1 January 2029. The 21 August amendment deleted that section, including listed measures such as closed-loop cooling, non-potable water and rainwater capture.

The Senate passed the amended bill on 26 August and ordered it to the Assembly. The current bill retains direct reporting to water suppliers and licensing authorities. It also requires urban water suppliers to include unconstrained demand from data centres and other large users when assessing current-year supply reliability and one dry year.

Analysis: deleting the statewide best-practice mandate narrows the bill, but licence-stage disclosure could still influence siting. Water suppliers and local authorities would receive project-specific demand figures before approval and could compare them with infrastructure limits and shortage scenarios.

Practical Actions For Developers And Water Suppliers

Developers should establish defensible calculation methods for maximum-day, maximum-month and average-year demand, then reconcile design estimates with cooling technology and water-source contracts. Existing operators should be able to separate direct on-site use from wider total use before licence renewal.

Water suppliers, cities and counties should assess how they would receive, validate and retain reports made under penalty of perjury. Investors, equipment suppliers and communities should track Assembly action and gubernatorial review before treating any reporting requirement as law.

Foresight's water stewardship topic tracks related water-use and resilience developments.

Summary

California AB 2619 would require data centre operators to disclose projected water demand before licensing and actual use at renewal. The 21 August amendment removed a proposed 2029 state guidance mandate but kept reporting and water-planning changes. The bill passed the Senate but remains proposed, with no special operative date in its current text.