Termites don’t announce themselves

A termite colony can work a house for years without the owner seeing a single insect. What they can’t do is avoid leaving evidence, and most of it is findable in an afternoon walk-around with a flashlight and a screwdriver. The seven signs below are the ones worth knowing, roughly in the order Fresno homeowners actually report them: wings on a windowsill after the first fall rain, pellets on a garage floor, and mud tubes noticed during some unrelated project under the house.

Two things frame everything below. First, each sign points toward a species, drywood or subterranean, and the two are treated completely differently, so the evidence is worth reading rather than just reacting to. Second, none of these signs tells you the size of the problem. That’s what a free inspection is for.

Each sign, and what it’s telling you

Mud tubes are the most conclusive sign there is. Subterranean termites dry out in open air, so they build covered highways of soil and saliva from the ground up to the wood. Look on foundation stem walls, crawl-space piers, inside the garage where the slab meets the wall, and where concrete steps or planters meet the house. Most tubes run in plain vertical lines, but they also hang as free-standing drop tubes from subfloors and hide in the gap between a porch and the siding. A tube means subterranean termites found the place, though not necessarily that they’re still active; an inspector breaks a section open and checks for workers, or watches whether the break gets repaired over the following week.

Frass is drywood evidence, and people vacuum it up for months before recognizing it. These termites live entirely inside the wood and push their droppings out through kick-out holes the size of a pinprick, leaving neat piles of hard, six-sided pellets that look like coarse ground pepper or tiny seeds. Garages, window sills, and attic framing are the usual spots. The test against sawdust: pellets are uniform, granular, and roll like sand between your fingers, while true sawdust is fibrous and clumps. Sawdust points to a beetle or a carpenter ant; pellets mean drywood termites, and a fresh pile means the gallery above it is live.

Swarmers indoors are a mature colony reproducing, and an indoor emergence almost always means the colony is in the structure itself. Discarded wings are the same event, discovered later. Swarmers shed all four wings within hours of landing, and the identical, veined wings pile up on sills, in bathtubs, and in spiderwebs long after the insects themselves are gone. Check the wings against each other: termite wings are all the same size, ant wings come in two.

The last three signs live in the wood. Hollow-sounding wood taps papery because termites eat the interior and leave a painted shell; run a screwdriver handle along fascia or baseboard and listen for the note to change. Blistered paint or rippled drywall paper traces galleries running just under the surface, and it fools people into repainting over an active infestation. Soft door frames, sills, and floors are the late-stage version, when the structural section is mostly gone. A screwdriver tip pressed into suspect wood settles it fast: solid wood resists, eaten wood gives without argument.