CARB-Accredited MRR Verifiers of GHG Emissions

This website is for CARB-accredited GHG verifiers for CARB's Mandatory Reporting Regulation. Please contact us at with questions. 

Recent Updates

Cal e-GRRT Step by Step Guide for Verifiers

MRR Regulation (PDF) (MS Word)
List of Reporting Entity Contacts and COI Status for accredited verifiers (as of 5/14/24)
CARB Verification Services Audit Checklist
Application for Upgrade to Lead Verifier or to add Sector

Verifier Accreditation Training

Training FAQ - The February 2024 MRR verifier accreditation training was completed. To attend a future training, please email

Errata (as of 2/23/24)

Course 1 (Verifier Training)
Course 1 recordings
1.1 slides | b/w
1.2 slides | b/w
1.3 slides | b/w
1.4 slides | b/w 
Handouts | case study | case study answers

Course 2 (Transactions)    
Course 2 recordings
2.1 (Electric Power Entities) slides | b/w | 2.1.CS w/o answers | Handouts)
2.2 (Transportation Fuel Suppliers) slides | b/w
2.3 (Natural Gas Suppliers) slides | b/w
2.4 (Carbon Dioxide Suppliers) slides | b/w
Course 2.2-2.4 Handouts

Course 3 (Oil and Gas)
Course 3 recordings
3.1 (PNG Systems) slides | b/w
3.2 (Refineries) slides | b/w
3.3 (Hydrogen Production) slides | b/w
Case Studies

Course 4 (Process emissions training from 2015)


Verifier Kickoff Webinar March 6, 2024 slides | recording

Links to previous webinars for accredited verifiers



Reporting guidance is posted on the guidance page.
Technical Guidance for Assuring Measurement Device Data Accuracy
Example Calculation for Verification of Reprocessed Tomato Product Data

Listserve Information
There are 2 CARB listserves related to GHG Mandatory Reporting:

  1. Public reporting & verification list (ghg-rep).  You may subscribe/unsubscribe yourself, including changing your email address.
  2. MRR accredited verifier-only list (ghgverifiers).  Please send an email if your email address changes.  Verifiers cannot update this list without CARB assistance.