Does Grafton, WI need an earthquake retrofit?

Under the seismic model IBC and ASCE 7 use for new construction, Grafton is Category B. Low seismic hazard. Code requires basic seismic detailing (bracing, connections) but no special structural system restrictions. Nationally, Grafton ranks above 17% of the 4,875 cities in this dataset for seismic hazard - the 17th percentile.

Where Grafton sits in Wisconsin

The raw figures: peak ground acceleration 0.033g, short-period spectral response 0.068g, 1-second spectral response 0.045g. Among 157 Wisconsin cities in this dataset, Grafton ranks 83 for seismic hazard, the 47th percentile within the state. About 12,741 people live in Grafton, Wisconsin.

Bracing and bolting: the actual cost

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

Earthquake insurance for a Grafton home

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 Grafton address.

More on how this number was built

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