Bainbridge Island's Seismic Design Category, explained

Under the seismic model IBC and ASCE 7 use for new construction, Bainbridge Island is Category D. High seismic hazard - this is the category most of coastal California, the Pacific Northwest, and other active fault regions fall into. Code mandates significant seismic detailing and restricts irregular structural configurations. This is the category the Brace + Bolt scope (cripple-wall bracing, foundation bolting) is built for. Rank it against the rest of the country and Bainbridge Island sits at the 93th percentile for seismic hazard among 4,875 US cities.

Where Bainbridge Island sits in Washington

The raw figures: peak ground acceleration 0.613g, short-period spectral response 1.442g, 1-second spectral response 0.506g. Among 125 Washington cities in this dataset, Bainbridge Island ranks 14 for seismic hazard, the 90th percentile within the state. About 24,618 people live in Bainbridge Island, Washington.

Retrofit economics for Bainbridge Island

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

Earthquake insurance for a Bainbridge Island 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 Bainbridge Island address.

More on how this number was built

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