Ottawa's Seismic Design Category, explained

Under the seismic model IBC and ASCE 7 use for new construction, Ottawa is Category B. Low seismic hazard. Code requires basic seismic detailing (bracing, connections) but no special structural system restrictions. Nationally, Ottawa ranks above 48% of the 4,875 cities in this dataset for seismic hazard - the 48th percentile.

How Ottawa compares

The raw figures: peak ground acceleration 0.074g, short-period spectral response 0.145g, 1-second spectral response 0.072g. Among 330 Illinois cities in this dataset, Ottawa ranks 72 for seismic hazard, the 78th percentile within the state. About 18,775 people live in Ottawa, Illinois.

What a retrofit costs in Ottawa

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 Ottawa address.

More on how this number was built

The methodology guide covers exactly how USGS's public design-maps API produced Ottawa'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.