Building an underground bunker in Texas.

Licensing and codes

Texas licenses the trades rather than the builder. Anyone doing electrical work must be licensed by the Texas Department of Licensing and Regulation, with an exemption for owners working on the home they live in, and plumbers are licensed by the State Board of Plumbing Examiners. The state commission that once oversaw residential construction was abolished in 2009.

Outside city limits, counties have limited authority. Under Chapter 233 of the Local Government Code, new homes must follow the International Residential Code, but counties have no power of prior approval or zoning. In McLennan County, for example, the county does no inspections and builders arrange third-party inspections themselves. We have every Styrkholm shelter in Texas engineered and inspected regardless.

Clay and limestone

Houston Black clay, the state soil, covers about 1.5 million acres of the Blackland Prairie from north of Dallas toward San Antonio and has very high shrink-swell potential. West of the Balcones Escarpment, the Edwards Plateau is hard limestone and dolostone under thin, rocky soils, and the Edwards aquifer is a karst system of caves and conduits.

On clay, the shelter needs drainage and backfill that keep moisture steady around it. On limestone, the question is the cost of rock excavation, so we price rock only after test borings and compare going down against building at grade and berming earth over the structure.

Flash floods

Flash Flood Alley runs along the Balcones Escarpment from about Waco to Uvalde. On July 4, 2025, the Guadalupe River near Hunt rose 26 feet in 45 minutes, and the flooding killed 137 people across Texas. An underground shelter in the wrong place becomes a trap. FEMA does not support placing shelters where floodwater could endanger occupants, and the ICC 500 shelter standard does not permit below-ground shelters in a mapped flood hazard area. We site every Texas shelter above the flood path first and design everything else second.

Tornadoes and storms

The National Weather Service reports that Texas averages 137 tornadoes a year, more than any other state. FEMA's safe room criteria design for 250 mph winds regardless of location, and an in-ground shelter gains debris protection from the soil around it. FEMA also notes that in-ground units must be anchored so rising groundwater cannot push them up. On the coast, 14 first-tier counties and part of Harris County require state windstorm inspection for TWIA coverage.

Radon

A Texas Tech study for the state found a first-floor average of 1.46 picocuries per liter, but a basement average of 7.85, nearly twice the federal action level. The highest readings were on the Central High Plains and the Central Texas Uplift. That basement figure is the one that matters for a bunker, so every Texas shelter we build gets mitigation and a test.

Earthquakes, wildfire and septic

Earthquake rates in the Permian Basin have risen sharply over two decades, which the U.S. Geological Survey links to deep wastewater injection; a magnitude 5.0 in 2020 was likely induced. The 2024 Smokehouse Creek fire burned about 1.075 million acres across Texas and Oklahoma, the largest wildfire in Texas history. Septic systems fall under TCEQ's on-site sewage program and are permitted by local authorized agents.

How we build in Texas

Texas rates Selective on our HOLM map: the right parcel works, with real tradeoffs. We look in the Hill Country above the floodplains and in northeast Texas, away from the coast. Many Texas clients start with a single engineered shelter that doubles as a tornado safe room, then build out the compound around it.

Escape openings

The International Residential Code, which these states and most of their counties build from, has a Section R310 that requires an emergency escape and rescue opening in basements and in every sleeping room below grade. A bunker is designed around that from the start: a second way out, sized and protected so it can be opened from inside after a storm, a fire or a collapse at the main entry. Some states amend R310, Utah among them, so we confirm the local version for each site.

Questions

This page is general information, current to October 2026. It is not engineering or legal advice. Codes, snow loads and frost depths are set locally and change; we confirm every requirement for a specific Texas parcel with the responsible jurisdiction before design.