Bill
AB 2619
California data centers must report detailed water use and efficiency measures to water suppliers and agencies, guiding statewide planning and drought planning.
Jurisdiction: California | Session: 2025-2026 | Sponsor: Assembly Member Papan (co-sponsor: Diane Papan)
Purpose and intent
- The bill aims to address the water resource implications of data center growth in California. It seeks to establish mandatory reporting by data centers on water use, create state guidelines to maximize water efficiency for data centers, and integrate data-center water demand into urban water management planning and shortage contingency processes. The bill also directs state agencies to develop guidance and best practices for evaluating data-center water use, efficiency measures, and cumulative water-resource impacts.
Key provisions and changes
1) Data-center water-use reporting (Business and Professions Code)
- Before applying for an initial city/county business license, equivalent instrument, or permit, a data-center owner/operator must provide to its water supplier (under penalty of perjury) an estimate of:
- Expected water use
- Anticipated water source
- Projected water-use volume for maximum day, maximum month, and average year
- On an initial license application to a city, the same information must be reported (perjury).
- On renewal of a license/permitting instrument, data centers must report the data-center’s annual water use for the preceding year, including:
- Total water use
- Direct water use (onsite usage, including cooling, sanitation, irrigation, etc., by source)
- Indirect water use (water used to produce electricity for the data center)
- The cooling system type must be disclosed as part of direct water use.
2) Data-center reporting in county processes
- Substantially the same reporting requirements apply to county-level initial licenses, equivalent instruments, or permits, including annual reporting for renewals.
3) Guidelines and best practices (Water Code 10609.1)
- By January 1, 2029, the Department of Water Resources (DWR) and the State Energy Resources Conservation and Development Commission (CEC) must develop guidelines and best practices to maximize efficient use of natural resources for technology needs, aligned with urban-water-use objectives and, where applicable, Energy Star.
- Required best practices include:
- Use of closed-loop cooling systems
- Use of nonpotable water where feasible
- Rainwater and stormwater capture infrastructure
- Scalable water-efficient indoor/outdoor practices
- Consideration of cooling-water intake structures to minimize environmental impact
- The agencies must also develop guidance for cities/counties to assess projected water use, efficiency measures, and cumulative water-resource impacts of proposed data centers within local/regional water management objectives.
4) Data-center demand in urban water-management planning (Water Code amendments)
- Data-center demand must be added to:
- Annual water supply and demand assessment (10632 and related provisions)
- Annual water-shortage contingency planning (10632.1) and related reporting
- Specifically, the annual assessment must include data-center demand, and the shortage-contingency plan must reflect data-center impacts and related actions.
5) Definitions
- Data center: Facilities housing computing infrastructure (servers, storage, networking, etc.) with power and cooling systems for processing/storing/distributing electronic data.
- Data-center types (for reference in the bill):
- Type I: hyperscale, >10,000 kg/m2 and >10,000 servers or >25 MW
- Type II: 2,000–50,000 kg/m2 and 2–25 MW
- Type III: 500–5,000 kg/m2 and <2 MW
- Water supplier: Community water system or urban water supplier (as defined by Health/Water Code provisions)
6) Significant procedural/timeline aspects
- Reporting requirements apply at initial license application, license renewal, and per-licensing actions for cities and counties (and equally for counties for data centers).
- A mandatory timeline: guidelines and best practices due by January 1, 2029.
- Urban water-management plans must incorporate data-center demand and related actions, with annual reporting due by July 1 each year (or earlier if imported-water allocations necessitate it).
- If relying on State Water Project or Bureau of Reclamation allocations, the annual assessment deadline can be adjusted (within 14 days after final allocations or by July 1, whichever is later).
State-mandated-local program or fiscal notes
- The bill expands perjury-related obligations (potential penalties) for reporting.
- It asserts statewide concern over water conservation, applying to all cities, including charter cities.
- No state reimbursement is required for mandated local costs under the bill’s provisions.
Impact and who is affected
- Affects data-center owners/operators (types I–III) in California.
- Requires upfront and ongoing reporting to water suppliers and licensing authorities.
- Encourages state-guided best practices to improve water efficiency and environmental safeguards for data-center cooling and energy-water nexus.
- Integrates data-center water demand into urban water-management planning and drought-response regimes.
Compiled from official sources — confirm details with the bill’s official record.
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