Termites cause roughly $5 billion in damage and control costs across the United States every year, affecting an estimated 600,000 homes. The average homeowner who discovers termite damage spends about $3,000 on repairs. The good news is that termite infestations are preventable and treatable, especially when caught early. Understanding which type of termite you’re dealing with, what signs to look for, and how treatments work puts you in a much stronger position to protect your home.
Types of Termites That Infest Homes
Three main types of termites target residential structures, and they differ in size, behavior, and the kind of damage they cause. Knowing which one you’re dealing with matters because the treatment approach is different for each.
Subterranean Termites
These are the most common and most destructive. Subterranean termites live and breed in soil, sometimes many feet below the surface, and require constant moisture. They reach your home’s wood either through direct soil contact or by building mud shelter tubes up your foundation. Workers are small, wingless, and light caramel-colored. Reproductive swarmers are dark brown to brownish-black with grayish wings. Subterranean termites are found across nearly every region of the country, from coastal areas to mountain elevations and even some desert zones.
Formosan termites are an especially aggressive subterranean species. They can build above-ground “carton nests” in addition to underground colonies, swarm at dusk, and are drawn to lights. Formosan termites alone account for at least $1 billion to $2 billion in U.S. damage and control costs annually.
Drywood Termites
Drywood termites nest above ground in relatively dry wood: lumber, utility poles, fences, dead tree limbs, even furniture. They don’t need soil contact or much moisture at all, which makes them harder to prevent through moisture management alone. They’re larger than subterranean termites and most prevalent in southern states and coastal regions. Their feeding creates chambers and tunnels that cut across the wood grain, and they leave behind distinctive fecal pellets: tiny, six-sided, uniform grains that look a bit like coarse sand.
Dampwood Termites
Dampwood termites infest wood that stays consistently wet, either from soil contact or a water leak. They’re also larger than subterranean species and create large, open galleries inside the wood where they live and feed. You’ll find them most often in cool, humid coastal areas. In homes, they’re typically a sign that something else is wrong first: a plumbing leak, poor drainage, or wood sitting directly on damp ground.
Signs of a Termite Infestation
Termites work from the inside out, so visible damage often means the infestation has been active for a while. The earlier you catch the warning signs, the less expensive the fix. Here’s what to watch for:
- Mud shelter tubes. Pencil-width tubes of dried mud running up your foundation wall, support piers, or plumbing pipes. These are highways subterranean termites build to travel between soil and wood while staying protected from open air. Check both outside your foundation and inside your crawl space.
- Swarmers or discarded wings. Winged termites emerging from walls, ceilings, or floors, or piles of shed wings on windowsills and near light sources. Swarmers indoors almost always mean an active colony is living in the structure.
- Pinholes in walls or ceilings. BB-sized spots of dried mud on drywall or paneling. These appear when termites accidentally break through to the surface and quickly patch the hole with mud.
- Sunken lines in paint or wallpaper. Narrow, winding trails or sunken areas beneath painted surfaces. Termites feeding on the paper backing of drywall can create these visible tracks without ever breaking the surface.
- Fecal pellets. Small piles of uniform, six-sided pellets on a floor, countertop, or windowsill. This is the signature of drywood termites, which push their dry droppings out of “kick-out holes” in the wood.
- Structural sagging. A floor that feels spongy, a door frame that crumbles when touched, or a roofline that dips. If damaged timbers contain galleries packed with dried dirt, that’s termite damage.
How Liquid Soil Treatments Work
For subterranean termites, the most common professional approach is a liquid chemical barrier applied to the soil around your foundation. The termiticide is injected along the perimeter, creating a treated zone that termites must pass through to reach your home. Older products worked by repelling termites outright, but newer formulations use a different strategy. They kill slowly enough that contaminated termites carry the chemical back to the colony and spread it to nestmates, including the queen, soldiers, and workers that never leave the nest. This transfer effect increases the overall impact well beyond the termites that directly contacted the treated soil.
A full liquid barrier treatment is typically priced by the linear foot of your foundation perimeter, not by your home’s square footage. For a typical 2,000-square-foot home with roughly 180 linear feet of foundation, expect $900 to $2,160 for a perimeter treatment, or $1,200 to $2,500 for a whole-house treatment that includes interior injections.
Baiting Systems
Termite bait stations are plastic housings installed in the ground around your home at regular intervals. They contain wood strips or compressed cellulose that termites encounter during their normal underground foraging. The stations don’t attract termites; they simply sit in the termites’ path until workers happen to find them, the same way termites stumble onto any other food source underground.
Once termites are feeding on a station, the wood is replaced with bait containing a slow-acting insect growth regulator. This chemical disrupts the ability of immature termites to molt, which means they can’t grow or develop normally. Because workers share food with every member of the colony, the chemical gradually reaches reproductives, soldiers, and nest-tending workers that never forage on their own. The slow action is intentional: if the bait killed on contact, only the first few termites would die, and the rest of the colony would simply avoid the station.
No chemical treatment, liquid or bait, is 100% effective every time. Both methods require professional monitoring and sometimes retreatment.
Treating Drywood Termites
Because drywood termites live entirely inside the wood they eat, with no connection to the soil, soil treatments don’t work against them. Treatment options fall into two categories: whole-structure and localized.
Whole-structure fumigation (tenting) involves sealing the entire house under a gas-tight tarp and introducing a fumigant gas that penetrates all wood in the structure. You’ll need to vacate the house for two to three days. The major advantage is that fumigation reaches every infestation, including hidden colonies behind walls or in attic framing that no inspection could detect. Costs range from $1,300 to $4,500 for most homes, though in high-demand markets like California the range can stretch from $920 to over $13,000 depending on house size.
Spot treatments target a single board or small group of boards where drywood termites have been confirmed. They cost $220 to $900 and work well for minor, accessible infestations. The limitation is that current detection methods aren’t reliable enough to guarantee you’ve found every colony in the house. If termites are hiding in areas you can’t inspect, a spot treatment will miss them.
Preventing Termites Before They Arrive
Most termite prevention comes down to two principles: eliminate easy access and reduce moisture. A few specific maintenance habits make a significant difference.
Keep your siding at least 6 inches above the soil line. Anything lower gives termites a hidden path onto the structure and invites wood decay. Never let mulch touch your foundation or lowest row of siding. Mulch holds moisture and gives termites covered access to your home’s exterior. When landscaping, leave at least a visible gap between any ground material and the building.
Don’t dig up or add new soil within 12 inches of your foundation. If your home has been treated with a soil termiticide, disturbing that zone lets termites bridge the chemical barrier. Termites can exploit foundation cracks as narrow as 1/32 of an inch, so sealing visible cracks in your foundation footer helps close entry points.
Moisture is the biggest controllable risk factor. Fix standing water or persistently wet soil in your crawl space, which may require installing a perimeter drain along the foundation wall. Repair plumbing leaks promptly. Ensure gutters and downspouts direct water away from the foundation rather than pooling against it. Homes with chronic moisture problems are more attractive to subterranean and dampwood termites alike.
Professional Inspections
Most pest control companies offer a free termite inspection as a sales lead, which is useful but comes with an obvious incentive to recommend treatment. An independent inspection from a licensed inspector who isn’t selling services typically costs $75 to $200. These independent inspections are required for VA loans and many conventional mortgage closings during real estate transactions.
During an inspection, the technician checks your foundation perimeter, crawl space, attic framing, and any accessible wood for mud tubes, termite damage, moisture problems, and conditions that invite infestation. Even if no active termites are found, the inspector should flag risk factors like wood-to-soil contact, poor drainage, or untreated cracks. Annual inspections are the single most reliable way to catch an infestation before the repair bill climbs into the thousands.