Tomball's Seismic Design Category, explained

Under the seismic model IBC and ASCE 7 use for new construction, Tomball is Category A. Lowest seismic design category. Building code requires no seismic-specific detailing here beyond ordinary construction practice. That puts Tomball in the 12th percentile nationally for seismic hazard - higher than 12% of the 4,875 US cities USGS was checked against here.

Where Tomball sits in Texas

The raw figures: peak ground acceleration 0.033g, short-period spectral response 0.069g, 1-second spectral response 0.04g. Among 384 Texas cities in this dataset, Tomball ranks 225 for seismic hazard, the 42th percentile within the state. About 15,152 people live in Tomball, Texas.

Retrofit economics for Tomball

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

What this means for insurance

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 Tomball address.

More on how this number was built

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