Climate Resilience Zoning

Overview

On February 27, 2023, the Cambridge City Council adopted new zoning requirements to address the long-term impacts of increased flooding and heat from climate change. They are based on the City’s climate projections over the next 50 years and will be updated from time to time.

The new requirements apply to:

  • Development that is already subject to Green Building Requirements. These include buildings that are 25,000 square feet or more in floor area.
  • All other newly constructed buildings, and enlargements of existing buildings that increase the footprint by at least 50%. These would include new houses and major enlargements, but would not include minor renovations or small additions.
  • Creation of occupiable or habitable space in basements that is exempt from Gross Floor Area (GFA) requirements (Flood Resilience only).
  • Increases in surface parking on a site (Green Factor only).

Flood Resilience Standards

These standards require new development to protect vulnerable spaces that have a likelihood of flooding based on future climate projections.

  • Review Section 22.80 of the Zoning Ordinance for detailed requirements.
  • Review the City’s FloodViewer tool to see if there are “Long-Term Flood Elevations” (LTFEs) that apply to a site. These are currently based on 2070 projections. Look at both Precipitation and Sea Level Rise / Storm Surge (SLR/SS) flood elevations – the higher of the two will be applicable.
  • If there are no LTFEs above the site grade, then no changes to the design will be necessary.
  • If there are LTFEs above the site grade, then new occupiable spaces will need to be protected from flooding up the 10%-probability LTFE. New habitable spaces (such as residential sleeping and living areas) will need to be protected up to the 1%-probability LTFE.
  • The standards became effective on September 1, 2023.
  • Any project that is subject to the requirements will need to submit a package of materials to be reviewed for compliance before a building permit (or special permit, if applicable) is issued. The package will include elevation drawings of the building showing the applicable LTFEs on the site and a description of how vulnerable areas will be protected. For more information on Flood Resiliency Standards and Applying for A Flood Resilience Compliance Confirmation please view the Flood Resilience Compliance Guidance Document in Flooding Resilience Standards.
  • Department of Public Works (DPW) Engineering staff will review for compliance.

Application and Review Process

Before each of the following stages of review, a full set of materials must be submitted to DPW to review and verify that the Flood Resilience standards are met.

  • Stage I: Special Permit Application (if applicable)
  • Stage II: Building Permit Application
  • Stage III: Certificate of Occupancy Application

Within 45 days after receipt of a complete set of documentation, DPW will provide a written notice whether the documentation sufficiently demonstrates compliance. 

With comments or questions on the Flooding Resilience Standards included in the Climate Resilience Zoning please email floodviewer@cambridgema.gov

Green Factor Standard

This new performance-based standard encourages heat mitigation through site and landscape designs that have a cooling benefit. Sites will need to achieve a “Cool Score” by including features like trees (both preserving mature trees and planting new trees), shrubs and other plantings, green roofs, shade canopies, and cool pavements.

  • Review Section 22.90 of the Zoning Ordinance for detailed requirements.
  • Review an example Cool Score Sheet and Site Plan to see what features are included in the score and how the score is calculated.
  • Review Cool Score Guidelines for information on how to appropriately design landscape features to have a cooling benefit.
  • Any project that is subject to the requirements will need to submit a package of materials to be reviewed for compliance before a building permit (or special permit, if applicable) is issued. The package will include a landscape plan showing areas that contribute to the Cool Score and a completed worksheet calculating the Cool Score based on the plan.
  • Community Development Department (CDD) staff will review for compliance.

Application and Review Process

Before each of the following stages of review, a full set of materials noted in the Green Factor Certification Form must be submitted to CDD to review and verify that the Green Factor standards are met. Contact CDD staff (cddzoning@cambridgema.gov) at CDD for an editable file of Cool Score Sheet.

  • Stage I: Special Permit Application (if applicable)
  • Stage II: Building Permit Application
  • Stage III: Certificate of Occupancy Application

Within 30 days of receiving the materials, CDD will provide a response that the application meets City requirements, or request additional materials to complete its review. Documents must be updated as the site or building design changes and submitted to CDD for continued review.

Other Zoning Changes

Under the new zoning, some improvements are easier than they used to be. For example, the following features may now to be exempt from some zoning limitations:

  • Shaded, open porches
  • Solar canopies
  • Outdoor steps and ramps providing access to raised ground floors
  • Usable green roofs
  • Increases in building height to compensate for raising above projected flood elevations

Review Article 5.000 of the Zoning Ordinance for detailed development standards. Refer to Article 2.000 of the Zoning Ordinance for definitions.

A Resilience Narrative must also now be provided for Project Review Special Permit Applications per Article 19.000 of the Zoning Ordinance.

Task Force Process

The Climate Resilience Zoning was recommended by a task force of community partners including residents, housing and commercial developers, institutions, climate change experts, and City staff.

For More Information

Contact cddzoning@cambridgema.gov.