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Signs of Termites: What Each One Tells You

By James Frame7 min read

A sign of termites is a physical trace the insects left behind, not the insects themselves. Every sign below is worth acting on, and the two you are most likely to find, a mud tube and a pile of pellets, cannot tell you whether the colony is still alive.

The Environmental Protection Agency notes that termites rarely emerge from soil, mud tubes, or the wood they are tunneling through, so most people stay unaware until a swarm appears or construction uncovers the damage. That is the shape of the whole subject: you are reading traces, and each trace answers a different amount of the question. If you have a visible trace on your wall or trim and want it routed to the right page, my termite scan walkthrough will place it.

What are the first signs of termites?

The first signs of termites are usually indirect traces left during feeding or travel, rather than the insects themselves. University of Florida extension entomologists say that structural infestations by a subterranean colony are usually not readily visible, and that the damage tends to be found during remodeling or once foraging activity becomes obvious.

UC IPM points out that most homeowners only discover a problem when an inspection happens during a real estate transaction, when damaged wood turns up during a room remodel, when a shelter tube appears on a wall, or when thousands of winged insects suddenly swarm in a bathroom or kitchen.

Because different species leave completely different evidence behind, knowing whether you are dealing with subterranean vs drywood termites early on keeps you from looking for the wrong clues.

What does a mud tube look like?

A mud tube is a line of dried earth running across a foundation wall, a support pier, a sill plate, or a floor joist. UC IPM calls these shelter tubes the most commonly seen evidence of a subterranean termite infestation, and says workers build them from saliva mixed with soil and bits of wood or even drywall. The University of Kentucky puts the size at about the diameter of a pencil, sometimes thicker, and says subterranean termites build them for shelter as they travel between their underground colonies and the structure.

If you break a tube open, UC IPM says you may see live workers and soldiers running through it, and Kentucky describes the workers as small and creamy-white. That settles it in one direction only. Kentucky is explicit that a vacant tube does not necessarily mean the infestation is inactive, because termites often abandon sections of tube while foraging elsewhere in the same structure. So live workers confirm an active infestation, and an empty tube leaves the question open. My guide to termite mud tubes has the four kinds of tube, how they get through a foundation, and what to do with one.

Why are there wings on my windowsill?

Discarded wings on a windowsill mean that winged reproductives, also called swarmers, have recently emerged inside or right next to your home. The University of Kentucky notes that swarmers are attracted to light, which is why they routinely accumulate around windows and exterior doors. Texas A&M extension specialists recommend checking light fixtures, cobwebs, and windowsills for termite bodies and shed wings.

Kentucky extension entomologists explain that indoor swarmers live for only about a day and are completely incapable of damaging wood themselves. A broom or a vacuum cleaner is all you need to handle the insects on your floor.

Where those insects emerged changes what the swarm means for your house:

  • In the yard: Kentucky notes that swarmers emerging from tree stumps or woodpiles out in the yard are not automatically a cause for concern and do not prove the house is infested.
  • Near the foundation: Swarmers emerging right next to your foundation, or from an abutting porch or patio, mean there is a strong chance the home is infested too.

Before assuming you have termites, check the body. Kentucky notes that termites have straight antennae, a uniformly thickened waist, and wings of equal size, where an ant has elbowed antennae, a pinched waist, and forewings longer than the hind wings. If you have a specimen and want to work through that properly, my guide on flying ants vs termites takes it one feature at a time.

What is the pile of grit under my trim?

A pile of hard grit under a baseboard or window frame is usually fecal pellets pushed out by drywood termites. The University of Florida extension explains that these termites live inside the wood and push their droppings out through kickout holes, openings usually one to two millimeters across.

The pellets have six hexagonal sides, and UC IPM says that shape is diagnostic for drywood termites. UF/IFAS says they collect in piles or in scatter circles below the hole, depending on how high the hole sits above the surface. The University of Arizona adds a place worth checking that nobody thinks of: pellets turn up caught in spider webs.

UC IPM states that it is not possible to determine from fecal pellets alone whether an infestation is currently active, or how far it extends through the wood. Cleaning up around the kickout hole and checking back a few days later helps, and UC IPM’s own caveat goes with it: building vibration and movement can shake pellets loose too. If what you found is a pile rather than a tube, my guide to termite droppings versus sawdust sorts it against carpenter ant shavings and beetle powder.

Does hollow-sounding wood mean termites?

Hollow-sounding wood often points to internal feeding, but physical probing provides a clearer answer than tapping alone. The Environmental Protection Agency recommends examining exposed wood by probing for hollow spots using a flathead screwdriver or a similar hand tool.

UC IPM notes that wood damaged by termites typically remains thin at the surface and is easily punctured with a knife or screwdriver. Arizona extension entomologists add that careful probing with a sharp instrument can disclose hidden galleries, which are the hollowed-out tunnels termites carve along the wood grain.

Kentucky extension entomologists note that termite-damaged wood is hollowed out along the grain and features bits of dried mud or soil lining the feeding galleries. If you probe a hollow section and find clean galleries with no soil in them, you may be looking at a different insect, and my guide to termite vs carpenter ant damage reads the opened wood four ways.

What do termites do to drywall and paint?

Termites put tiny soil-rimmed holes through drywall and make the surface above them ripple. The University of Kentucky notes that termites occasionally bore small holes through drywall or plaster with bits of soil around the margin, and that rippled or sunken traces behind wall coverings can indicate them tunneling underneath. The soil around the margin is what separates one of these from a nail pop or a popped screw, and a nail pop leaves nothing behind it.

On painted wood the coating distorts as the wood under it goes. UF/IFAS says blistering or peeling of thin surface wood or paint is an external sign of drywood termites. UC IPM adds that darkening or blistering of structural wood members is another possible indication, and that the wood in a damaged area is typically thin at the surface.

Can I have termites and see none of this?

Yes, and this is the part of the subject people are most often reassured out of. Kentucky’s extension says termites are cryptic and that infestations can go undetected for years behind walls, floor coverings, insulation, and other obstructions. It goes further: damage can progress undetected even in exposed wood, because the outer surface usually stays intact. Kentucky adds that even the most experienced inspector can overlook signs that are hidden.

The people who write the inspection rules build that in. North Carolina’s Structural Pest Control Division says an inspection is by law the careful visual examination of all accessible areas of a building, plus the sounding of accessible structural members in the places most open to attack. It then says the operator is not responsible for any evidence that was inaccessible at the time, and tells buyers to note the areas the form lists as inaccessible.

UC IPM points out that the telltale signs often sit in dark and sometimes hazardous places, attics or tight crawlspaces with nails, dust, or standing water, which is why it recommends a licensed professional rather than a homeowner going to look. It also notes that one building can hold several colonies of the same species, or several different species at once. My read of those three together is that seeing nothing is good news about the parts of the house you can see, and says nothing at all about the rest.

What should you do if you find signs of termites?

If you find a suspicious sign in your home, your immediate response should be to document the evidence rather than panic. The University of Kentucky emphasizes that termites damage wood slowly, so taking an additional day, week, or month to gather facts and make an informed decision is generally inconsequential. You do not need to sign a contract on the spot.

Here is what I would do if I found a potential termite trace in my own home:

  1. Take clear photographs: Photograph the specific sign up close, capturing clear detail of any soil margins, pellet shapes, or tube pathways, then take a wider photo showing where the feature sits in the room.
  2. Document the location: Write down the exact date, time, and structural location where you found the trace, noting whether you cleaned up any debris or broke open a mud tube.
  3. Book an inspection rather than buying a product: UC IPM says do-it-yourself pesticides for use against termites are generally not effective, and recommends contacting a licensed professional for the inspection and whatever follows it.

I would spend some of the time that buys me on the company rather than on the insect. My guide to how to vet a pest control company covers what to check before you call, and a termite inspection is the visit that reaches the attics and crawlspaces UC IPM warns you off going into yourself.

I would also check the rest of the house before the visit rather than after it. The printable inspection checklist is that walk written out: 23 things you can look at yourself, in the order you would come across them, with what a positive looks like beside each one.

I have not seen your house. What I can say is that none of the signs above is an identification on its own, that the two most common ones cannot tell you whether anything is still feeding, and that the days you spend documenting and getting a second opinion cost you nothing that matters.

Sources

Common questions

Can I have termites without seeing any of these signs?

Yes, and the people who write the inspection rules say so. Kentucky's extension service notes that termite damage can progress undetected even in exposed wood, because the outer surface usually stays intact, and that the most experienced inspector can still miss what is hidden. North Carolina's regulator puts the same thing from the other side: an inspector is not responsible for evidence that was inaccessible on the day. Seeing nothing is genuinely good news. It is not proof.

I broke open a mud tube and it was empty. Am I in the clear?

No, and this is the most common wrong conclusion in the whole subject. Kentucky's extension says plainly that a vacant tube does not necessarily mean the infestation is inactive, because termites often abandon sections of tube while foraging somewhere else in the same structure. An empty tube tells you a colony reached that spot at some point. It cannot tell you where they are now.

I swept up the pellets and more came back. Does that prove it is active?

It points that way, and there is a caveat worth knowing. UC IPM recommends exactly that test, cleaning up around the kickout hole and checking a few days later, and in the same sentence notes that building vibration and movement can shake old pellets out of wood that nothing lives in anymore. So fresh pellets after a sweep are a reason to book an inspection, not a finding on their own.

The swarm came out of a stump in the yard. Does my house have termites?

Not necessarily, and Kentucky's extension draws the line at the foundation. Termites swarming from tree stumps or woodpiles out in the yard do not automatically mean the house is infested. Swarmers coming out next to the foundation, or from a porch or patio attached to the house, are a different matter, and Kentucky says there is then a good chance the home is infested as well. Note where they came out before you note anything else.

  • identification
  • mud tubes
  • swarmers
  • frass
  • inspection

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