Does South Barrington, IL need an earthquake retrofit?

South Barrington carries Seismic Design Category B under USGS's ASCE 7-16 model. Low seismic hazard. Code requires basic seismic detailing (bracing, connections) but no special structural system restrictions. Rank it against the rest of the country and South Barrington sits at the 37th percentile for seismic hazard among 4,875 US cities.

Where South Barrington sits in Illinois

The raw figures: peak ground acceleration 0.061g, short-period spectral response 0.12g, 1-second spectral response 0.061g. Among 330 Illinois cities in this dataset, South Barrington ranks 235 for seismic hazard, the 29th percentile within the state. About 5,061 people live in South Barrington, Illinois.

Bracing and bolting: the actual cost

Outside California, no state-level retrofit grant equivalent to Brace + Bolt could be found for Illinois. A typical retrofit still runs $5,000-$10,000 nationally, about $7,000 for a common single-family job.

Insuring against this, not just retrofitting

Outside California, earthquake coverage is typically sold as an endorsement added to a standard homeowners policy, not a separate product - worth asking about directly when getting a home-insurance quote for a South Barrington address.

More on how this number was built

The methodology guide covers exactly how USGS's public design-maps API produced South Barrington's numbers. The guide to what a Seismic Design Category actually means covers why a category is never a substitute for an engineer's assessment of one specific house.