Termite injection treatment involves drilling into concrete slabs, soil, or infested wood and injecting liquid termiticide directly where termites live and travel. It’s the most common professional method for eliminating subterranean termites after construction, and a variation of it is also used for localized drywood termite infestations. The average homeowner pays between $75 and $1,750 depending on the size of the infestation and how much of the home needs treatment.
How Slab Injection Works
Most homes with termite problems have subterranean termites entering through cracks in the concrete slab or along the foundation. To stop them, pest control technicians drill small holes vertically through the slab along all cracks and construction joints. These holes are spaced 12 inches apart and placed no more than 6 inches from the foundation wall. Through each hole, liquid termiticide is injected into the soil beneath the slab, creating a continuous chemical barrier between the ground and your home.
The standard application rate is 4 gallons of diluted termiticide per 10 linear feet, per foot of depth. The goal is to saturate the soil from the bottom of the slab down to the top of the footing, closing off every route termites use to reach the structure. After injection, the drill holes are patched with cement or a similar filler. The result is an invisible barrier in the soil that termites can’t cross without picking up a lethal dose of the chemical.
What Chemicals Are Used
Modern termiticides work differently than older products. Rather than creating a wall that repels termites on contact, the most widely used active ingredients have a delayed effect. Termites walk through treated soil without immediately detecting the chemical, pick it up on their bodies, and carry it back to the colony. There, normal grooming and food-sharing behavior spreads the toxin to nestmates that never touched the treated soil. Lab studies have confirmed that exposed termites cause secondary deaths among unexposed colony members through this transfer.
The three most common active ingredients in professional injection treatments are fipronil, imidacloprid, and chlorfenapyr. All three share this delayed-action property, which makes them far more effective at collapsing entire colonies rather than simply redirecting foraging tunnels to a new entry point. Because the termites don’t detect the chemical as a threat, they continue moving through treated soil zones normally, maximizing exposure throughout the colony.
Foam Injection for Localized Infestations
When termites are living inside wood, particularly drywood termites that don’t need soil contact, technicians use a different approach. Small holes are drilled directly into the infested wood, and insecticidal foam is injected into the termite galleries. The foam expands to fill hollow spaces, coating internal surfaces with a residual layer of active ingredient. A typical application lasts about 10 seconds per injection point, or until foam begins backing out of the hole. The injector tip stays in place for a few extra seconds to allow all the foam in the tube to dispense into the wood.
This method is used for spot treatments rather than whole-structure protection. It works well when the infestation is confined to identifiable areas, like a window frame, door jamb, or section of wall framing. For widespread drywood termite infestations across multiple rooms, fumigation (tenting the entire house) is often more practical, though significantly more expensive.
Cost Breakdown
Chemical termiticide injection runs $3 to $16 per linear foot, making it one of the more affordable professional treatment options. For comparison, bait station systems cost $8 to $12 per linear foot plus ongoing bait replacement, and full-house fumigation typically runs $5 to $20 per linear foot, with total costs of $2,500 or more. The national average for termite treatment overall is around $621, though a large home with an extensive infestation requiring comprehensive slab injection will land closer to the upper end of the range.
Price varies based on several factors: the linear footage of your foundation, how many areas need drilling, whether the infestation has reached multiple entry points, and your region. Some companies charge a flat fee for the initial treatment and then offer an annual warranty renewal for a separate cost.
Safety During and After Treatment
The termiticides used in soil injection are designed to bind to soil particles once applied. This keeps the chemical in the treatment zone around your foundation rather than migrating through the environment or leaching into groundwater. Once the soil surface is restored after treatment, the product stays underground where it was placed.
During the actual application, technicians will ask you to keep children and pets away from the work area. You should also remove toys, pet dishes, and any outdoor items from treatment zones before the crew arrives. Once the job is done and the soil surface has been filled back in or patched, the treated areas pose minimal risk for surface contact. The chemical is locked in soil several inches below grade, not sitting on surfaces your family touches.
What Happens After Treatment
Don’t panic if you still see termites in the weeks after injection. Termites that were already inside your walls at the time of treatment can remain active for six to eight weeks before dying off. They only need a gap of 1/32 of an inch to move through structures, so stragglers working their way through existing tunnels are normal. What you’re watching for is new activity months later, which could indicate a gap in the chemical barrier.
Retreatment is only warranted under specific circumstances: clear evidence of re-infestation, disruption of the barrier from construction, excavation, or landscaping, or confirmed breakdown of the termiticide in the soil. If your pest control company recommends retreatment, they should be able to point to one of these causes.
Warranties and What They Cover
Most professional termite treatments come with a warranty, but the details vary significantly between companies. A warranty should spell out the time period of coverage, renewal options and cost, the company’s obligation to retreat if termites return, and whether they’ll repair any termite damage that occurs during the warranty period. It should also specify which areas of the structure are covered. If the warranty doesn’t include your entire home, the covered zones must be listed explicitly.
Pay attention to conditions that could void your warranty. Certain actions on your part, like adding a new patio, digging near the foundation, or stacking wood against the house, can break the chemical barrier and give the company grounds to deny a claim. Ask for the warranty terms in writing before treatment begins, and keep a copy with your home records. An annual inspection, often tied to warranty renewal, is the best way to catch any new activity before it becomes a full-blown infestation again.