Lewiston, ID: what USGS's seismic model says

Lewiston carries Seismic Design Category C under USGS's ASCE 7-16 model. Moderate seismic hazard. Code adds irregular-building restrictions and requires bracing of some nonstructural components (e.g. tall shelving, water heaters) in addition to structural detailing. That puts Lewiston in the 73th percentile nationally for seismic hazard - higher than 73% of the 4,875 US cities USGS was checked against here.

How Lewiston compares

USGS's underlying values for Lewiston: 0.132g peak ground acceleration, 0.297g at short period, 0.107g at 1 second. Within Idaho alone, Lewiston ranks 23 of 36 cities by seismic hazard - the 37th percentile in-state. Lewiston has a population of about 34,693.

Retrofit economics for Lewiston

A full earthquake retrofit typically runs $5,000-$10,000 nationally (around $7,000 typical), driven mainly by house size and foundation type, not by Idaho specifically. California's Earthquake Brace + Bolt grant, which covers a large share of this cost, is a California-only program and does not apply in Idaho.

Insuring against this, not just retrofitting

A Lewiston homeowner cannot buy a standalone earthquake policy in most cases - it is added to an existing homeowners policy as an endorsement, so the place to start is a regular home-insurance quote.

Where Lewiston's figures come from

Lewiston's Category C and every number above trace to USGS's own ASCE 7-16 Design Maps service - see the methodology guide. See the category explainer for what Category C does and doesn't tell you about Lewiston.