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Subterranean Termite Treatment — Liquid Barrier & Colony Elimination
Subterranean termites enter through the soil and travel through mud tubes to reach wood. Western subterranean termites are the most destructive termite species in California — a single colony can contain hundreds of thousands of workers. Termidor liquid barrier treatment eliminates the colony by transfer effect.
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How Subterranean Termite Treatment Works
Subterranean termites live in the soil and forage up through the ground to find wood. Because the colony lives underground, treatment must reach the soil to be effective — surface sprays alone are inadequate. A liquid termiticide barrier applied to the soil around and beneath the structure is the standard-of-care treatment.
Termidor (fipronil) is the industry-leading product for this application. Termites that contact the treated soil are not killed immediately — instead, they carry the active ingredient back to the colony on their bodies, exposing the queen and thousands of nestmates. This "transfer effect" eliminates colonies that would otherwise be impossible to reach directly.
In addition to liquid barriers, baiting systems (such as Sentricon) can be used to intercept foraging workers and deliver a slow-acting toxicant back to the colony. Our inspectors recommend the approach best suited to your structure, soil conditions, and infestation severity.
The Treatment Process
Inspect and Assess
A licensed inspector confirms subterranean termite activity, identifies entry points, mud tubes, and conducive conditions, and maps the treatment zone.
Trench and Treat
A trench is excavated around the foundation and treated with Termidor liquid termiticide. Slabs and concrete flatwork are drill-treated and patched.
Monitor and Confirm
A follow-up inspection confirms the colony has been eliminated. Annual monitoring is recommended to maintain the protective barrier.
Signs You Have Subterranean Termites
Mud Tubes
Pencil-width tubes of soil running up foundation walls, piers, or plumbing penetrations — the primary indicator of subterranean termite activity.
Swarmer Emergence
Winged termites (alates) swarming in spring, often near windows and light sources. Subterranean swarmers typically emerge after winter rains.
Damaged Wood
Wood that sounds hollow when tapped, or wood showing a honeycombed interior with soil-packed galleries (unlike drywood galleries, which are clean).
Frass or Pellets
Note: subterranean termites do not push frass out of galleries. Clean pellets indicate drywood termites; soil-packed galleries indicate subterranean.
Subterranean Termite Treatment Cost
Subterranean termite treatment typically runs $800–$2,500 depending on the linear footage of the structure perimeter, soil conditions (hard soil or concrete requiring drill treatment costs more), and the extent of infestation.
Inspections are free throughout our primary service area (Orange County and bordering cities). We provide a written quote before any work begins. There is no upfront cost to have one of our licensed inspectors assess your property.
Frequently Asked Questions
What is the most effective treatment for subterranean termites?
Termidor (fipronil) liquid barrier treatment is widely considered the most reliable option for subterranean termites. It uses a transfer effect — termites that contact the treated zone carry the active ingredient back to the colony, eliminating it at the source.
How long does a subterranean termite treatment last?
Termidor liquid barrier treatments are typically effective for 10+ years in the soil. Annual inspections are recommended to monitor for any new activity and confirm the barrier remains intact.
Do I need to leave my home during subterranean termite treatment?
No — liquid barrier treatment is applied to the soil around the perimeter of the structure. Occupants are not required to vacate during or after treatment.
How much does subterranean termite treatment cost?
Subterranean termite treatment typically costs $800–$2,500 depending on the structure's perimeter, soil conditions, and extent of infestation. A free inspection is required before we can provide an accurate quote.
Will subterranean termite treatment damage my landscaping?
Minimal impact. Trenching is performed around the foundation perimeter and any slabs are treated through small drill holes that are patched afterward. Concrete flatwork, landscaping plants, and irrigation lines are generally unaffected.
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