Testing for termites starts with a careful visual inspection of your home’s foundation, crawl spaces, and wood structures for telltale signs like mud tubes, fecal pellets, or hollow-sounding wood. Most homeowners can spot the major warning signs themselves, though professional inspectors use thermal cameras and moisture meters to detect hidden colonies behind walls. Here’s how to do both effectively.
What Termite Evidence Actually Looks Like
The signs depend on which type of termite you’re dealing with, but three categories of evidence cover most situations: mud tubes, fecal pellets, and damaged wood.
Mud tubes are the most common sign of subterranean termites, the species responsible for the majority of structural damage in the U.S. These pencil-width tunnels run along foundation walls, support piers, and plumbing pipes, connecting the colony in the soil to the wood it’s feeding on. Tubes made from a mix of saliva, soil, and wood bits can appear on exterior foundations, interior walls, or even ceilings. To check whether a tube is active, break open a small section and look for tiny, creamy-white worker termites inside.
Fecal pellets signal drywood termites, which live entirely inside the wood they eat rather than in the soil. Drywood termites push their dry waste out of small “kick-out holes,” creating small piles of uniform, six-sided pellets on floors, countertops, or windowsills. These pellets are roughly the size of poppy seeds and feel gritty, like coarse sand. Finding a pile is often the first and only visible clue of a drywood infestation.
Damaged wood may not be obvious from the surface. Termites eat wood from the inside out, so a beam or door frame can look perfectly fine while being hollowed internally. Tap suspect wood with the handle of a screwdriver. Solid wood produces a sharp, ringing sound. Infested wood sounds dull or hollow, and a screwdriver can often push straight through the surface into soft, gallery-riddled wood behind it. You may also notice sunken or wavy lines under paint or wallpaper where termites have eaten the material just beneath the surface.
Swarmers and Wings
Once a year, mature termite colonies release winged reproductive termites (swarmers) that fly out to start new colonies. Finding a cluster of dead swarmers on a windowsill or a pile of shed wings near a window or light fixture is a strong indicator of a nearby colony. Swarms typically happen in spring or early summer for subterranean species, though timing varies by region. Don’t confuse termite swarmers with flying ants. Termite swarmers have straight, beaded antennae, a thick waist, and two pairs of wings that are equal in length. Flying ants have elbowed antennae, a pinched waist, and front wings longer than the back pair.
Less Obvious Signs to Watch For
Some termite evidence is easy to overlook. BB-sized dots of dried mud on interior walls or ceilings are “pinholes,” spots where termites accidentally broke through the surface and quickly patched the opening. Horizontal streaks of dried mud under eaves can indicate Formosan termites, an especially aggressive subterranean species. Mud tubes can also travel over or tunnel through foam insulation boards, so don’t assume insulation is a barrier.
Many homeowners first discover termite damage accidentally during remodeling, when they pull away wallpaper or tear out drywall and find galleries packed with dried dirt running through the wood behind it.
Where to Inspect Your Home
A thorough DIY inspection should cover these areas in order of priority:
- Foundation walls (interior and exterior): Walk the entire perimeter looking for mud tubes running up from the soil line. Check for cracks or gaps where termites could enter.
- Crawl spaces: Inspect wooden supports, floor joists, and any wood in contact with soil. This is the single highest-risk area in most homes and the one most often skipped.
- Basement: Look for damage on wooden beams, walls, and subfloor. Basements stay humid and dark, which subterranean termites prefer.
- Wood-to-soil contact points: Deck posts, fence posts, porch steps, and any framing that touches the ground are prime entry points.
- Window and door frames: Check sills and frames for soft spots, especially near ground level.
- Attic: Inspect rafters and roof sheathing. Drywood termites can establish colonies up here since they don’t need soil contact.
- Garage: Check walls, the foundation, and stored cardboard or firewood that could harbor or attract colonies.
Bring a strong flashlight, a flathead screwdriver for probing, and a mirror or phone camera for tight spaces. You’re looking for mud tubes, pellet piles, hollow wood, and moisture damage in every area.
How Professionals Test for Termites
Professional inspectors start with the same visual checks you would, but they add technology to find activity hidden inside walls and under floors. The most common tools are moisture meters, thermal imaging cameras, and acoustic detectors.
Thermal imaging cameras capture surface temperature differences across walls, ceilings, and floors. Active termite galleries and the moisture they generate create temperature variations that show up as contrasting colors on the camera’s screen. A professional-grade camera with high thermal sensitivity can scan large areas quickly, flagging zones that warrant closer investigation. Consumer-grade thermal attachments for smartphones exist but are significantly less sensitive and less reliable for pest detection.
Acoustic emission detectors pick up the vibration signatures of termites chewing through wood. These are more targeted tools, used to confirm activity in a specific area rather than scan an entire house. An inspector might use a thermal camera to identify a suspicious wall section, then place an acoustic sensor against it to listen for feeding.
Neither tool alone confirms a termite diagnosis. Inspectors verify thermal or acoustic findings with a moisture meter, physical probing, or a borescope (a tiny camera on a flexible cable inserted through a small drilled hole) before writing anything into the report.
What a Professional Inspection Costs
For a standard single-family home under 2,000 square feet, a termite inspection typically runs $75 to $150. If you’re buying or selling a home, you’ll need a formal wood-destroying organism (WDO) inspection from a licensed inspector, which costs $100 to $200. In high-volume termite states like California, Texas, and Florida, real estate inspection fees cluster between $125 and $175.
Larger or more complex properties (above 3,500 square feet, multi-unit buildings, or homes with extensive crawl spaces) can run $200 to $400 or more. If you enroll in an annual inspection program, most companies discount repeat visits by 20 to 30 percent.
How Often to Inspect
Annual inspections are the standard recommendation for homes in termite-prone regions, which includes most of the southern U.S. and coastal areas. If your home has a history of termite treatment, has wood siding, sits on a pier-and-beam foundation, or is surrounded by trees and mulch beds close to the structure, yearly checks are especially important. Homes in colder northern climates with lower termite pressure can typically go two to three years between professional inspections, though a quick personal check of the foundation each spring is still worthwhile.
What to Do If You Find Evidence
If you find swarmers indoors, you can remove them with a broom or vacuum. They’re harmless and won’t start a new colony inside your house. What they signal, though, is a mature colony somewhere nearby, likely in or under the structure.
The most important thing to know is that termites work slowly. The damage caused by waiting an extra week or even a month to make a decision is generally inconsequential. Get quotes from at least two or three licensed pest control companies. Any firm that pressures you into signing a contract immediately with scare tactics or limited-time offers is a red flag, not a sign of urgency. Take your time, compare treatment approaches and warranties, and choose a company that explains what they found, where they found it, and exactly what the treatment plan involves.