Slope Protection

Questions? Contact SSPA

1660 Mission Street- 1st Floor
San Francisco, CA 94103-2414
(415) 558-6360

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The Slope Protection Act was passed by the Board of Supervisors in 2008 and required construction of new buildings or structures and certain other construction work on properties subject to the Slope Protection Act undergo additional review for structural integrity and effect on slope stability. 

The legislation was amended and renamed the Slope & Seismic Hazard Zone Protection Act in 2018. The amended Slope & Seismic Hazard Zone Protection Act applies to all property within San Francisco that exceeds an average slope of 4H:1V (25%) or falls within certain mapped areas of the City, except those properties already subject to the Edgehill Mountain Slope Protection Area or the Northwest Mt. Sutro Slope Protection Area.

Seismic Hazard Zone Map 

San Francisco Seismic Hazard Zones Map

 Slope Map

Slope Map

What is being impacted?

  1. Properties are subject to the requirements of this ordinance if: (1) any portion of the property lies within the areas of the "Earthquake Induced Landslide Zones" in the Seismic Hazard Zone Map, release by the California Department of Conservation, Division of Mines and Geology, dated November 17, 2000 or (2) the property exceeds an average slope of 4 horizontal to 1 vertical (4H:1V) per Topographic Map of San Francisco: 4H:1V Slope dated July 25, 2018; and 
  1. Proposed construction involves the following: (1) construction of a new building or structure having over 1,000 square feet of new projected roof area; (2) horizontal or vertical addition having over 500 square feet of new projected roof area; (3) shoring; (4) underpinning; (5) grading, including excavation or fill, of over 50 cubic yards of earth materials; or (6) or any other construction activity that, in the opinion of the Building Official, may have a substantial impact on the slope stability.

Projects Exempted from SSPA Ordinance:

The following projects are exempted from the SSPA Ordinance and do not require completion or submittal of the SSPA Checklist:

  • Proposed construction without plans.
  • Proposed construction without structural alterations or grading with less than 50 cubic yards of earth materials.


What do I need to do?

If your property lies within areas specified in Item 1 and your proposed construction involves activities indicated in Item 2, you will be required to submit additional reports by a license professional identifying areas of potential slope instabilities, defining potential risks of development due to geological and geotechnical factors, and recommending appropriate slope instability mitigation strategies. Additionally, your project may require a third party peer review to provide additional and specialized expertise to supplement the Department of Building Inspection plan review; the Building Official may also elect to establish a Structural Advisory Committee to review the proposed project.

For more details on SSPA requirements, please reference Information Sheet S-19.