Cap-and-invest third-party verification

In 2022, the Greenhouse Gas (GHG) Reporting regulation was updated to include a broader group of industries and to align with the requirements of the cap-and-invest program. It was also updated to include an additional quality-assurance mechanism: third-party emissions verification.

Emissions reports submitted to us are reviewed and verified by our staff. Under the updated rule, certain reporters must also contract with a third-party verifier. These independent verifiers will review each entity's annual emissions reports and send us a statement each year indicating whether or not the reports are accurate.


How do I know if my business needs to hire a third-party verifier?

All businesses that are subject to, or are voluntary participants in, the cap-and-invest program are required to have their emissions reports verified by a third-party verifier. However, other businesses reporting emissions under Chapter 173-441 may also be required to do so, depending on their emissions levels:

  • Threshold for reporting emissions: 10,000 metric tons
  • Threshold for third-party verification: 25,000 metric tons
  • Threshold for coverage under cap-and-invest: 25,000 metric tons after accounting for exemptions set in state law.

In addition, any reporter that drops below the 25,000 MT CO2e threshold must still have its emissions reports verified for the first year. 

Resources for reporters

How do I find a third-party verification body?

We are in the process of setting up a program for third-party verification bodies to become certified in Washington. Washington-certified verification bodies will be listed here soon.

In the meantime, we anticipate significant overlap with both the California-accredited verification bodies and Oregon-certified verification bodies. We encourage you to reach out to them with questions about their processes.

Upcoming trainings

Upcoming third-party verification trainings for emissions reporters will be listed here, once scheduled. Please email GHGReporting@ecy.wa.gov to be added to an email list for announcements about upcoming trainings.

For trainings on how to report emissions, see our Emissions page.

Forms for reporters and third-party verifiers are currently in development and will be available through the GHGReg website for registered reporters and verifiers.

Verification tips for reporters


Resources for verifiers

Both verification bodies and individual verifiers must meet certain requirements to be certified in Washington, including:

Individual verifiers must also complete the Washington third-party verification training. Both lead verifier and specialized sector certification require demonstration of additional work experience and corresponding certification.

All eligible verifiers and verification bodies are invited to register in Washington using our GHGReg application

Upcoming trainings

Upcoming verifier trainings will be listed here once scheduled. Please email GHGReporting@ecy.wa.gov to be added to an email list for announcements about upcoming trainings.

Forms for reporters and third-party verifiers are currently in development and will be available through the GHGReg website for registered reporters and verifiers.

Conflict of interest

The purpose of the third-party verification requirement is to ensure submitted emissions reports are accurate. To serve this purpose, it is important that verifiers be impartial when reviewing reporter submissions. This requires avoiding any potential conflict of interest as outlined in Chapter 173-441-085 (7)(c)  

Conflict of interest can be: 

  • Low: verification relationship will be approved 
  • Medium: verification may proceed with an approved mitigation plan
  • High: verification relationship will not be approved.