California’s Climate Corporate Data Accountability Act, commonly known as SB 253, reaches its first reporting deadline on August 10, 2026.
The California Air Resources Board (CARB) says the law covers U.S.-based entities doing business in California with more than $1 billion in annual revenue. First-year reporting covers Scope 1 and Scope 2 greenhouse gas emissions. Scope 3 reporting begins in 2027.
For teams near the finish line, the priority is controlled completion: confirm which entity and period must report, resolve material gaps, document judgements, and preserve proof of what was submitted.
Confirm applicability and reporting ownership
Do not rely on a sustainability team’s informal understanding of the corporate group. Legal, tax, finance, and sustainability should document:
- The U.S.-based reporting entity.
- The basis for doing business in California.
- The revenue measure and period used for the threshold assessment.
- Subsidiaries, operations, and joint arrangements included or excluded.
- The selected GHG consolidation approach.
- The executive owner and authorized submitter.
CARB’s initial regulation connects the revenue threshold to gross receipts reported to the California Franchise Tax Board. Complex groups should obtain legal advice on the facts that determine scope.
Use the correct emissions period
The first-year rule ties the applicable preceding fiscal year to the reporting entity’s year-end. The approved regulation provides different treatment for fiscal years ending on or before February 1 and those ending after February 1.
Confirm the period against the current CARB rulemaking materials, then lock it across the inventory, source files, review documentation, and submission. A polished report for the wrong period is still the wrong report.
Complete the Scope 1 inventory
Reconcile the source population to controlled facilities, vehicles, equipment, refrigerants, and other direct-emission activities. Check that:
- Every in-scope site has submitted data or an approved estimate.
- Fuel and refrigerant units are standardized before calculation.
- Factors and global warming potential values are identified and versioned.
- Biogenic CO2 and other required gases are treated consistently.
- Acquisitions, divestments, openings, closures, and outsourcing changes are documented.
- Source totals reconcile to the disclosed Scope 1 result.
Retain invoices, meter exports, maintenance records, calculation files, approvals, and explanations for estimates. The evidence should allow a reviewer to reproduce the number after the deadline.
Complete the Scope 2 inventory
Build a complete population of purchased electricity, steam, heat, and cooling. Reconcile accounts and meters to facilities and confirm that landlord-managed locations have not disappeared from the boundary.
Where GHG Protocol dual reporting applies, keep location-based and market-based calculations separate. Review supplier-specific factors and contractual instruments for quality criteria, geography, period, ownership, and retirement. Do not use a renewable-energy claim as a substitute for the underlying electricity calculation.
Check the first-year flexibilities
CARB’s March 2026 workshop materials state that the Scope 1 and Scope 2 template is not mandatory for 2026 and that limited assurance is not required for the first submission. Those flexibilities reduce filing friction, but they do not remove the need for a complete and supportable inventory.
Before filing, check CARB’s program page for the current intake process, templates, extensions, and regulatory status. Save the instructions used as part of the reporting evidence because online guidance can change.
Run a final submission control
Use a sign-off sheet that records:
- Applicability and period approval.
- Inventory-boundary approval.
- Scope 1 and Scope 2 reconciliation.
- Factor, unit, and formula review.
- Variance analysis against prior disclosures.
- Approval of estimates, exclusions, and methodology notes.
- Executive certification or internal authorization.
- Submission timestamp, confirmation, and final-file archive.
Freeze the submitted calculation version. Corrections should create a new version with an explanation rather than overwrite the record that supported the original filing.
Begin Scope 3 preparation now
The 2026 filing is not the end of the implementation. Scope 3 reporting starts in 2027, and CARB is continuing to develop detailed requirements.
Complete a category screening, identify material data owners, map supplier and customer information, and record methodology gaps now. The strongest starting point is a complete Scope 1 and Scope 2 process whose boundaries, factors, controls, and evidence can be extended to the value chain.
Information in this article was verified on July 26, 2026. CARB materials and legal requirements may change. This overview is not legal advice; consult the current rule and qualified counsel for your circumstances.
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