Termites work from the inside out, often feeding on wood for years before you notice any damage. That makes regular inspection essential, because by the time structural problems become obvious, the colony has had a long head start. The good news is that termites leave behind reliable clues, and knowing what to look for can help you catch an infestation early.
Mud Tubes on Your Foundation
Subterranean termites, the most common type in the U.S., build pencil-width mud shelter tubes to travel between their underground colonies and the wood they’re feeding on. These tubes protect them from open air and predators. During an inspection, look for them running up your foundation walls (both outside and inside the crawl space), along support piers, around plumbing pipes, and over foam insulation boards. They can also appear higher up on interior walls, ceilings, soffits, and fascia boards.
If you find a tube and aren’t sure whether it’s active, break off a small section and check back in a few days. Active colonies will rebuild it. Even if they don’t, the presence of tubes means termites have accessed the structure at some point, and a closer look is warranted.
Swarmers and Discarded Wings
Termite colonies release winged swarmers, usually in spring, to start new colonies. Finding swarmers emerging directly from your walls, ceiling, or floors is a strong indicator of an active infestation inside the structure. Even finding a handful of them indoors, or piles of small translucent wings on windowsills and near light fixtures, should raise a flag.
People often confuse termite swarmers with flying ants. Three features tell them apart quickly. Termite swarmers have straight, beadlike antennae, while ants have elbowed antennae that bend at a sharp angle. Termites have a thick, uniform waist; ants have a pinched, narrow waist. And termite wings are two pairs of equal length that break off easily, while ant wings are two pairs of noticeably different lengths. If you’re finding equal-sized wings scattered near your foundation or entry points, those came from termites.
Signs on Walls and Ceilings
Termites feeding behind drywall leave subtle but distinctive marks. Watch for narrow, sunken winding lines or depressed trails underneath paint, which result from termites eating the paper backing of the drywall just below the surface. You might also notice BB-sized spots of dried mud on interior walls or ceilings. These “pinholes” are spots where termites briefly broke through the surface and patched the opening with mud.
In areas where Formosan subterranean termites are present, particularly across the Gulf Coast states, you may see odd-shaped formations of dried mud sprouting from walls or ceilings in late spring. These are sometimes called swarm castles, structures the colony builds to launch swarmers from elevated positions inside your home.
Drywood Termite Pellets
Drywood termites don’t build mud tubes or need contact with the ground. They live entirely inside the wood they consume, which makes them harder to detect. Their most telltale sign is frass: tiny, six-sided fecal pellets that are uniform in size, roughly like grains of sand. Drywood termites push these pellets out of small “kick-out holes” in the wood, creating small piles on floors, countertops, or windowsills below the infested area.
These pellets are often mistaken for sawdust, but sawdust is irregular in shape and size while termite frass is distinctly uniform and has visible ridges when viewed closely. Subterranean termites don’t produce these pellets at all. They use their excrement to build their mud tubes instead. So if you find these neat little piles of granules near wood surfaces, you’re dealing specifically with drywood termites.
Wood Damage and Structural Clues
Subterranean termites eat along the wood grain, leaving behind feeding galleries lined with mud or soil. Drywood termites eat across the grain, hollowing out hidden chambers that weaken wood from the inside without obvious external signs. In both cases, damaged wood often looks normal on the surface but sounds hollow when you tap it.
During your inspection, probe exposed wood in crawl spaces, basements, and attics with a flathead screwdriver or a similar tool. Infested wood will feel soft and give way easily. You may also uncover galleries containing dried dirt when you peel away wallpaper, remove trim boards, or open up walls during remodeling. Structural symptoms like sagging floors, a dipping roofline, or door frames that crack or no longer close properly can indicate long-term termite damage, though these signs usually mean the infestation has been active for a significant period.
Where to Focus Your Inspection
Termites are drawn to moisture and wood-to-ground contact. Concentrate your inspection on these high-risk areas:
- Foundation perimeter: Walk the entire exterior, looking at every inch of the foundation wall for mud tubes, especially near where soil meets the structure.
- Crawl spaces: Check support piers, floor joists, sill plates, and any wood in contact with or close to the ground. Bring a flashlight and screwdriver.
- Basement walls: Look along the top of the foundation where the wood framing sits, around utility penetrations, and near any cracks in the concrete.
- Bathrooms and kitchens: Moisture from plumbing makes these areas attractive. Inspect under sinks, around tubs, and behind toilets.
- Window frames and door frames: Probe wood that seems warped or damaged, especially on ground-floor exterior walls.
- Attic: Drywood termites can infest roof framing and eaves. Look for frass piles and probe any suspect wood.
How Often to Inspect
Termite damage accumulates slowly but relentlessly. A single worker termite can feed on a structure for its entire 15-year lifespan, and queens can live and produce eggs for up to 50 years. Because termites nibble from the inside, damage is often extensive before it becomes visible. An annual inspection is a reasonable schedule for most homeowners, with more frequent checks in high-risk regions like the Southeast, Gulf Coast, and parts of California where termite pressure is heaviest.
If your home has had a previous infestation, or if you have older construction with wood-to-soil contact, inspecting twice a year (spring and fall) gives you a better chance of catching new activity early.
DIY Inspection vs. Professional Inspection
A homeowner walkthrough can catch the obvious signs: mud tubes on the foundation, swarmer wings on the windowsill, frass piles under a cabinet. It’s worth doing regularly, and now you know what to look for. But termites often infest areas that are difficult to access or see, inside wall cavities, under slab foundations, deep in crawl spaces. A licensed pest control operator has the tools and training to check these hidden spots, including moisture meters, acoustic detection, and sometimes infrared cameras.
Many pest control companies offer free initial inspections, making it easy to get a professional assessment without upfront cost. If an infestation is found, treatment pricing varies based on the type of termite, the size and construction of your home, the treatment method required, and your geographic region. Homes with crawl spaces or basements generally cost more to treat than homes on slab foundations, and fumigation (typically used for drywood termites) is more expensive than liquid or bait treatments used for subterranean species.
Reducing Your Risk
A few simple changes around your home make it less inviting to termites. Keep mulch, firewood, and lumber stored at least several feet from the foundation. Make sure soil doesn’t pile up against your siding or cover the top of your foundation wall, because termites can enter unseen when that transition point is buried. Fix leaky faucets, air conditioning drip lines, and downspouts that dump water near the foundation. Good drainage and ventilation in crawl spaces reduce the moisture that subterranean termites need to survive.
Seal cracks in concrete foundations and around utility penetrations. Trim vegetation away from exterior walls so you can maintain a clear line of sight along the foundation during your inspections. None of these steps guarantee termite prevention, but they eliminate the easy entry points and the moisture conditions that colonies rely on.