The SB 253 deadline is no longer a moving target. On October 12, 2026, California's Office of Administrative Law approved CARB's Initial Regulation, officially confirming November 10, 2026 as the due date for first-year Scope 1 and Scope 2 emissions reports. That leaves in-scope companies roughly two weeks.
We've spent the past several months helping companies prepare their first SB 253 filings. The regulation itself is short and simple. The decisions it requires companies to make are not. Here is what we keep seeing, and where first-time filers are losing time they don't have.
Where SB 253 stands today
- Deadline: November 10, 2026, for Scope 1 and Scope 2 emissions from your preceding fiscal year.
- Who files: U.S. business entities with more than $1 billion in total annual revenue that do business in California. Applicability is assessed entity by entity.
- Assurance: the statute calls for limited assurance starting in 2026, but CARB will accept first-year submissions with or without it.
- How to file: CARB's voluntary intake platform, or by email to climatedisclosure@arb.ca.gov.
- Litigation: the Ninth Circuit paused SB 261 in November 2025. It did not pause SB 253.
For the most up-to-date CARB guidance on SB 253 and SB 261, see our article here.
Lesson 1: "Good faith" is a test about December 5, 2024, not about effort today
CARB's first-year flexibility comes from its December 2024 Enforcement Notice. Companies can report Scope 1 and 2 based on information they already had, or were already collecting, when that notice was issued. Companies that were not collecting that data, and were not planning to, are asked to submit a statement of non-reporting on company letterhead before November 10.
Many teams read this as "submit whatever you have and nothing happens." That reading is wrong in three ways.
- The discretion covers incomplete reporting, not non-submissions. Filing nothing at all is not protected, and the statute allows penalties of up to $500,000 per reporting year. Our breakdown of SB 253 and SB 261 penalties covers how that works.
- The non-reporting statement is a factual claim about your data on a specific date. If your facilities team was tracking fuel and electricity in 2024, even informally, signing a letter that says otherwise creates a problem you'll have to explain later. Treat the letter as a legal document, because it is one.
- CARB isn’t your only audience. SB 253 reports will be publicly available, so customers, investors and lenders can see who filed, who didn’t, and what they reported. Most B2B contracts require compliance with all applicable laws, and enterprise customers already ask suppliers for emissions data. A missing or thin filing can come up in a renewal conversation long before CARB acts on it.
On top of all this, whether you report partial data or file a non-reporting statement, the flexibility only lasts one cycle. CARB's 2027 proposals add Scope 3 and limited assurance on top of Scope 1 and 2.
Lesson 2: The number you've already published may not work as your SB 253 number
CARB accepts an existing annual report or Scope 1 and 2 data you've already submitted to another program, such as CDP. That flexibility is real, and it can save time. It also tempts teams to resubmit a figure without checking whether it fits.
Before you reuse a number, check three things:
- Period: does it match the fiscal year from Lesson 1?
- Boundary: does it cover the entity that's actually in scope? A parent can file one consolidated report for its subsidiaries, but each in-scope subsidiary remains responsible for its own compliance.
- Method: is your organizational boundary approach (operational control, financial control, or equity share) stated and applied consistently?
Your first reporting year numbers matter more than you might think. CARB has proposed that, from 2027, methodology or boundary changes moving your inventory more than 5% from your base year would trigger a recalculation of prior years. A rushed 2026 figure can become an expensive one to correct.
Lesson 3: Scope 2 emission factors are where most errors live
CARB does not require a specific emission factor dataset for 2026. That sounds simple until you hit the eGRID (regional grid emissions data) problem.
Most U.S. companies calculate location-based Scope 2 emissions with the EPA's eGRID factors, and the EPA did not release eGRID 2024 on its usual schedule. CARB's guidance allows either the most recent official release (eGRID 2023), the eGRID 2024 dataset published by the Cornerstone Sustainability Data Initiative, or another credible source, and encourages companies to name the factors and sources used.
What we see in practice: factor vintages mixed across facilities, market-based results reported without saying they're market-based, and global warming potential values that nobody can trace back to a source. None of these will stop a submission this year. All of them will come up the first time an assurance provider looks at the file.
Pick your factor sources, apply them consistently, and record the choice somewhere it won’t get lost.
Lesson 4: CARB wants more than a total, even where it doesn't require it
The minimum for 2026 is your annual Scope 1 and Scope 2 emissions. CARB's guidance goes further and encourages companies to add context: methodologies, data sources, global warming potential values, emission factors, organizational boundaries, emissions broken out by category and gas, and key assumptions. Our walkthrough of CARB's Scope 1 and 2 reporting template shows how those fields are structured.
While these are not required in year 1, our advice is to provide them. That context is the same documentation limited assurance will demand, and it protects you when your SB 253 figure differs from a number a customer or investor saw somewhere else.
Lesson 5: Filing is easy; owning the data is hard
CARB's intake platform is straightforward. You can register contact and billing details for fee invoicing ahead of the deadline, then submit your data or non-reporting statement through the same platform.
The bottleneck is almost never the form. It's the fact that Scope 1 and 2 data lives in four places: utility bills with facilities, fleet fuel with operations or finance, refrigerant records with whoever services the HVAC, and the final sign-off with legal. When no single person owns the filing, each handoff costs days.
Name one owner now, with authority to chase every data source and a clear path to legal review. Longer term, it’s worth deciding how that data gets collected each year, since chasing spreadsheets across four teams won’t hold up once Scope 3 and assurance arrive. Our comparison of DIY spreadsheets, software, and consultants for carbon accounting walks through the tradeoffs.
Lesson 6: The fiscal-year question comes first, and it’s easy to get it wrong
SB 253 asks for emissions from your "applicable preceding fiscal year," defined in section 96076 of the regulation. For most companies, that means the fiscal year ending in 2025.
Companies whose fiscal year ends between January 1 and February 1, 2026 should report the fiscal year ending in 2026 instead.
The mistake we see most often happens before any calculation starts. A team pulls the totals from its latest sustainability report without checking which period that report covers.
Calendar-year inventories, 2024 baselines and fiscal-year inventories get mixed together, and the error only surfaces when finance asks why the revenue year and the emissions year don't match.
Lesson 7: Treat 2026 as the dry run for assurance and Scope 3
Limited assurance isn’t required in 2026, but CARB’s 2027 rulemaking proposes making it mandatory for Scope 1 and 2, along with reporting on five Scope 3 categories. Whether to add more categories is still under debate. Our recommendation is to screen all 15 Scope 3 categories now, so you know which ones matter before CARB decides which ones it requires.
For limited assurance, that means every decision you document this month – from the reporting period to the boundary to the emission factors – becomes the evidence trail an assurance provider will test next year.
Companies that treat November 10 as a one-off scramble will redo most of this work in 2027. Companies that build a repeatable process now won't. We've written more about this pattern in lessons from hundreds of corporate carbon footprints.
Two weeks out: where we'd focus
If your first SB 253 report isn't finished yet, these are the decisions that need an answer this week:
- Confirm applicability and the reporting period in writing, entity by entity.
- Decide between a report and a statement of non-reporting, and get legal to sign off on whichever you choose.
- Reconcile your SB 253 figure against anything you've already published to CDP, customers or in a sustainability report.
- Lock and document your Scope 2 emission factors and GWP sources.
- Register your contact and billing details on CARB's intake platform now, even if your data isn't final.
These are judgment calls, and they're the ones that are hardest to unwind after a report is on file with a regulator. Good.Lab pairs GHG emissions software with experts who have worked through these decisions with other first-year filers.
If you're two weeks out and still answering the questions above, talk to our team about SB 253 compliance.
SB 253 deadline FAQs
When is the SB 253 deadline? First-year Scope 1 and Scope 2 reports are due November 10, 2026, covering the preceding fiscal year. The date was confirmed when the Office of Administrative Law approved CARB's Initial Regulation on October 12, 2026.
Do we need third-party assurance for our first SB 253 report? No. The statute calls for limited assurance starting in 2026, but CARB will accept 2026 submissions whether or not assurance was obtained. CARB has proposed requiring limited assurance from the 2027 cycle.
What if we weren't tracking emissions in 2024? CARB asks companies that were not collecting, or planning to collect, Scope 1 and 2 data as of December 5, 2024, to submit a statement of non-reporting on company letterhead before November 10, 2026. This applies to the 2026 cycle only.
Is SB 253 on hold because of the lawsuit? No. The Ninth Circuit paused enforcement of SB 261, the climate risk disclosure law, but declined to pause SB 253. The November 10 deadline stands.
Can we submit our CDP data for SB 253? CARB accepts existing Scope 1 and 2 data reported to other programs, including voluntary initiatives. Check that the reporting period, entity boundary and methodology match SB 253's requirements before you submit it.
