Rialto's Seismic Design Category, explained

Rialto 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. Rank it against the rest of the country and Rialto sits at the 99th percentile for seismic hazard among 4,875 US cities.

Rialto by the numbers

The raw figures: peak ground acceleration 0.842g, short-period spectral response 2.005g, 1-second spectral response 0.789g. Among 429 California cities in this dataset, Rialto ranks 64 for seismic hazard, the 85th percentile within the state. About 104,918 people live in Rialto, California.

What a retrofit costs in Rialto

Because Rialto 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.

Earthquake insurance for a Rialto home

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 Rialto homeowner asking about it.

More on how this number was built

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