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Structural & retrofit

What is a Bay Area fault zone?

Bay Area fault zones are state-designated Alquist-Priolo zones along active faults — Hayward, San Andreas, Calaveras, Concord-Green Valley, and Rodgers Creek — where new construction across the fault trace is prohibited or heavily restricted. A geotechnical study is required for permits within designated zones.

Construction within Alquist-Priolo zones requires a fault-rupture study by a California-licensed geologist. Cost runs $4,500–$12,000; turnaround 4–10 weeks.

Existing structures within fault zones are not prohibited but face elevated insurance costs and may require seismic retrofit when triggered by significant remodels.

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Related questions

  • Is my Bay Area home on a fault line?
  • Do I need earthquake insurance in the Bay Area?
  • What does Alquist-Priolo mean?
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