Back to Policy Toolkit

CALGreen Data Collection

Effective July 1, 2024, CALGreen has mandatory embodied carbon requirements. The Carbon Leadership Forum is collecting whole building life cycle assessment (WBLCA) results conducted for compliance with CALGreen to inform future policy development.


The California Green Building Standards Code—Part 11, Title 24, California Code of Regulations—known as CALGreen, is a mandatory green building standards code. In August 2023, the California Building Standards Commission voted unanimously to pass two CALGreen amendments to reduce embodied carbon, making California the first state to address embodied carbon in a mandatory code.

Effective July 1, 2024, the new measures will apply to public and private non-residential buildings larger than 100,000 square feet, and schools larger than 50,000 square feet in size. Demonstrating a 10% reduction in global warming potential (GWP) using a cradle-to-grave whole building life cycle assessment (WBLCA) is one of three available pathways for compliance with the new measures. The other two pathways are building reuse (45% or greater) and using environmental product declarations (EPDs) to comply with product GWP limits, similar to Buy Clean California.

Why is the CLF collecting WBLCA data submitted to CALGreen?

In the new language (passed in 2023), CALGreen requires verification of compliance through a letter signed by a licensed design professional with a summary of the GWP analysis produced by the WBLCA software (e.g. Athena Impact Estimator, One Click LCA, tallyLCA). Given that the CALgreen requirements are a first-in-the-nation code requirement of this kind, analysis and lessons learned from this first phase could be critical in informing future policy and code development in California and across the nation. Straightforward compliance paths are important for widespread code implementation. However, these GWP results may be difficult to interpret, analyze, and use to inform meaningful future policy efforts in California, such as updates to CALGreen, due to the decentralized, flexible reporting format.

Therefore, the CLF is providing an opportunity for project teams to voluntarily contribute the results of their WBLCAs to the CLF for the purpose of conducting research and supporting future policy development. More details on this process will be provided in 2024, closer to the date of when this requirement will go into effect.

What is the scope of CALGreen’s WBLCA requirement?

CALGreen includes the following requirements on the scope of the WBLCA assessment:

  • Building components: Building components included in the scope of CALGreen’s requirements are limited to primary and secondary structural elements (footings and foundations, and structural columns, beams, walls, roofs, and floors) and enclosure (glazing assemblies, insulation, and exterior finishes) (5.409.2.1).
  • Reference study period: The reference study period of the proposed building shall be equal to the reference baseline building and shall be 60 years. (5.409.2.2)
  • Life cycle stages: CALGreen requires a cradle-to-grave assessment, which includes stages A-C. A cradle-to-gate assessment covering only A1-A3 stages would therefore NOT be compliant with this requirement.

As noted above, these new measures will apply to public and private non-residential buildings larger than 100,000 square feet, and schools larger than 50,000 square feet in size.

For a quick overview of whole-building life cycle assessment, consider visiting the WBLCA section of “Measuring Embodied Carbon.”

Interested in Sharing Your CALGreen Results?

Stay tuned! The CLF will provide a template in Spring 2024 for projects interested in sharing their CALGreen WBLCA results to support research.

In the meantime, please reach out with questions about this project at [email protected]

View all policy resources in our resource library