Healdsburg's Seismic Design Category, explained

Healdsburg clears the point where the standard Seismic Design Category tables stop applying - USGS returns no letter here, only a flag that a site-specific study (ASCE 7-16 §11.4.8) is required. Treat that as more severe than any lettered category, not as missing data. That puts Healdsburg in the 99th percentile nationally for seismic hazard - higher than 99% of the 4,875 US cities USGS was checked against here.

Where Healdsburg sits in California

The raw figures: peak ground acceleration 0.957g, short-period spectral response 2.202g, 1-second spectral response 0.854g. Among 429 California cities in this dataset, Healdsburg ranks 26 for seismic hazard, the 94th percentile within the state. About 11,231 people live in Healdsburg, California.

Bracing and bolting: the actual cost

Because Healdsburg is in California, the EBB grant applies if the ZIP code participates and the house qualifies (wood-framed house on a raised (not slab-on-grade) foundation, built before 1980): a $3,000-$7,000 bracing-and-bolting job drops to $0-$4,000 after the $3,000 base grant, or effectively free for income-eligible households getting the full $10,000.

Insuring against this, not just retrofitting

Earthquake coverage in California mostly runs through the California Earthquake Authority (CEA), sold only through licensed agents at CEA-participating insurers - there is no direct-to-consumer CEA policy. A general home-insurance quote is the practical starting point for a Healdsburg homeowner asking about it.

More on how this number was built

The methodology guide covers exactly how USGS's public design-maps API produced Healdsburg's numbers. The retrofit cost and grant guide covers every EBB eligibility rule, including the ones this page can't check.