SB253's Scope 1 & 2 Deadline: What November 10, 2026 Actually Requires

If your company falls under SB253, the date that matters right now is November 10, 2026: the first reporting deadline for Scope 1 and Scope 2 emissions. If you're reading this any time close to that date, this is the practical version of what it means and what's actually left to do.

Who this applies to

SB253 covers US-formed entities with more than $1 billion in annual revenue that do business in California. "Doing business in California" is interpreted broadly. It's not limited to companies headquartered here. Sales into the state, employees based here, or customers here can be enough to bring a company into scope, regardless of where it's actually based. If your revenue clears the threshold and you have any meaningful California footprint, assume you're covered until you've confirmed otherwise.

What "reporting" actually means

This isn't a rough estimate or a good-faith summary. The requirement is an auditable Scope 1 and Scope 2 emissions inventory, built to GHG Protocol standards. Auditable is the operative word. It means every number needs a source you can point to, a documented methodology, and a boundary decision you can defend, not just a total that sounds reasonable. That's the same standard covered in the four-pitfalls piece: fleet data pulled from actual fuel records rather than estimates, refrigerant recharge data tied to the reporting period, both required Scope 2 methods calculated, and an organizational boundary decided and applied consistently. An inventory that can't survive someone asking "where did this number come from" isn't compliant, even if the total happens to be roughly right.

Where that leaves you if you haven't started

If you're only now building this out, you're not in an unusual position. Plenty of first-time filers are in the same spot, because most companies newly covered by this law have never built a GHG inventory before and didn't know they needed to until relatively recently. What matters now is sequencing: get your organizational boundary decided first, since it determines which facilities, vehicles, and leased spaces are actually yours to report. Then pull the underlying records, fuel purchases, refrigerant logs, electricity bills, rather than trying to estimate your way to a number quickly. An inventory built on records holds up under scrutiny; one built on estimates usually doesn't, and re-doing it later costs more time than doing it right the first time would have.

What's not due yet

Scope 3, your supply chain emissions, is not part of this deadline. Those requirements are still in the proposal stage for 2027 and beyond, and the methodology for estimating supply chain emissions is a genuinely different, harder problem than Scope 1 and 2. Don't let Scope 3 anxiety pull attention away from the deadline that's actually in front of you. Get Scope 1 and 2 right first; Scope 3 is a separate project with its own timeline.

If you haven't started pulling data yet, the Scope 1 & 2 Data Collection Checklist walks through exactly what to gather and in what order. It's built around the same categories that trip up most first-time inventories.