Does Lewisville, TX need an earthquake retrofit?

Under the seismic model IBC and ASCE 7 use for new construction, Lewisville is Category B. 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 Lewisville sits at the 33th percentile for seismic hazard among 4,875 US cities.

Lewisville by the numbers

USGS's underlying values for Lewisville: 0.054g peak ground acceleration, 0.11g at short period, 0.056g at 1 second. Within Texas alone, Lewisville ranks 64 of 384 cities by seismic hazard - the 84th percentile in-state. Lewisville has a population of about 135,983.

Bracing and bolting: the actual cost

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 Texas 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 Texas.

What this means for insurance

A Lewisville 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 Lewisville's figures come from

Lewisville's Category B 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 B does and doesn't tell you about Lewisville.