If you live west of Mopac, you’ve probably found a scorpion in your house. If you live in West Lake Hills, Lakeway, Bee Cave, or Barton Creek, you’ve probably found multiple. The reason isn’t carelessness on your part or laziness on your pest control company’s part. It’s geology and biology, both of which favor the scorpion.
The geology
Austin sits on the eastern edge of the Edwards Plateau, the karst limestone formation that defines the central Texas Hill Country. The limestone is fractured and porous — it has been weathering for millions of years, and the surface and near-surface rock is laced with cracks, voids, and small spaces. These provide ideal microhabitats for the striped bark scorpion (Centruroides vittatus), the dominant scorpion species in Texas.
According to Texas A&M AgriLife Extension, scorpions occur in every county in Texas, but their abundance varies dramatically based on substrate. Sandy soils support fewer scorpions; limestone karst supports many. West Austin sits on limestone karst.
The biology of the striped bark scorpion
Centruroides vittatus is the most common scorpion in Texas and the only species typically encountered in residential settings in the Austin metro. It’s small (adults 1.5–2.5 inches), tan or pale brown with two darker stripes running the length of the back, and active primarily at night. During the day it harbors in cool, dark, narrow spaces — under rocks, in wood piles, in wall voids, in shoes left in garages.
The species is venomous but not medically significant for most adults. Stings are painful (often compared to a wasp sting) and cause localized swelling and numbness lasting a few hours to a day. The exception: small children, the elderly, and anyone with insect-venom allergies should treat scorpion stings as urgent.
Scorpions feed on insects — crickets, roaches, spiders, and smaller invertebrates. They are opportunistic hunters, not nest-builders. A scorpion in your house is not the start of an infestation; it’s a single animal that found a way in. The reason you see more in some neighborhoods than others is that more are present in the soil around the home.
Why they get into your house
Scorpions enter structures through: (1) weep holes in brick veneer, which are typically 3/8″ wide gaps designed for moisture drainage but which provide a direct path for scorpions; (2) gaps where utility lines (AC line sets, plumbing) penetrate the slab or foundation; (3) garage thresholds with gaps at the floor; (4) the slab-to-wall transition on some construction types; (5) gaps in the foundation around vents and crawl space access; (6) on legs or in folds of clothing left outdoors.
They are not seeking to be in your house. They are seeking cool, dark harborage during the day after night-time hunting. Your house provides cool dark harborage. So does a pile of rocks at your foundation. The latter doesn’t bother you; the former does.
What actually reduces scorpion pressure
1. Exterior residual treatment. Professional-grade product (pyrethroid + non-repellent combination) applied to the foundation perimeter, the rock landscaping immediately adjacent to the house, weep holes, and known harborage areas. This kills scorpions on contact and provides 30–60 days of residual effect. Consumer-grade pyrethrins do not work at typical OTC concentrations — the cuticle is too tough.
2. Exclusion at access points. Sealing weep holes with stainless steel mesh (the only material scorpions can’t squeeze through). Sealing utility penetrations. Adjusting garage thresholds. This is labor-intensive but produces permanent reduction.
3. Habitat modification at the foundation. Pulling rock landscaping back 18–24 inches from the foundation. Removing wood piles, leaf piles, and any debris against the house. Trimming foundation plantings to allow air circulation. Each of these reduces the harborage immediately at the foundation.
4. Reducing prey abundance. Scorpions feed on insects. Properties with significant insect populations support scorpion populations. General pest service that reduces the cricket, roach, and spider populations reduces the food base for scorpions. The two services work together.
What does not work
Ultrasonic plug-ins. Citronella. Cedar oil sprays. The “scorpion zapper” lights (they kill non-target insects more than scorpions). Citrus peels. Diatomaceous earth (works on insects with softer cuticles; scorpions walk over it).
OTC sprays at consumer concentrations don’t work because the cuticle is too tough. The same active ingredient at professional concentration, applied with appropriate technique, does work.