How fast can termites damage a home?

A mature subterranean colony of 60,000 workers consumes about 1 gram of wood per day per 1,000 termites — noticeable structural weakening usually appears within 3–8 years of colony establishment.

Do termite swarmers mean I already have damage?

Not necessarily. Swarmers can originate outdoors, but if you see them inside the home, an established colony is almost always present nearby.

Can I inspect for termites myself?

You can screen for the seven signs above monthly, but a licensed inspector uses moisture meters, thermal imaging, and probing tools that catch hidden galleries you cannot see.

Are termite droppings dangerous?

Frass itself is not toxic, but the wood dust can trigger asthma and indicates active feeding that needs professional treatment.

Pest Identificationdiagnostic · recognition9 min read

Signs of a Termite Infestation

Primary entity: Termite infestation · Parent: Wood-destroying organisms

Published 2026-01-15 · Updated 2026-06-01

Termites almost never show themselves. They tell you they are there through side-effects — a smear of soil on a wall, a wing on a windowsill, a floor that feels a half-inch softer than it did last spring. Reading those side-effects correctly is the whole job.

How a colony develops before you ever see a sign

Understanding the timeline explains why some signs appear months before others.

1
Year 0 — Swarm and pairing
A reproductive pair drops wings and burrows into soil or moist wood within 24 hours of a spring swarm.
Why it matters: This is why shed wings near a window are the earliest possible indoor signal.
2
Years 1–2 — Silent expansion
The pair produces a few hundred workers. Damage is confined to a single joist or sill; no exterior symptoms.
3
Years 2–4 — Mud tubes and moisture
Workers begin building shelter tubes to bridge concrete and reach wood above grade. Blistered paint appears where galleries meet drywall.
4
Years 4+ — Structural symptoms
Floors sag, doors stick, and the first swarmers leave the mature colony — often the moment homeowners finally call an inspector.

Early signs — colonies under two years old

These show up before any structural change is visible. One is enough to justify an inspection.

Discarded wings on windowsills after warm rain

Why it appears: Reproductive termites shed all four wings within hours of landing. The wings are equal in length, which distinguishes them from ant swarmers.
When you see it: March–May in most of the US, later in the Pacific Northwest.
What it tells you: A colony is either forming nearby or an existing colony is releasing new reproductives — often the same colony that has been feeding for years.

Pencil-thick mud tubes on foundation walls

Why it appears: Subterranean workers need 100% humidity and cannot cross open air. They build soil-and-saliva tubes to bridge concrete.
When you see it: Any month; fresh tubes are dark and damp, old tubes crumble.
What it tells you: Active tubes = current feeding path. Even a dry, abandoned tube proves colony traffic has occurred within about 12 months.

Six-sided pellets on baseboards or window sills

Why it appears: Drywood termites push waste out of their galleries through small kick-out holes; the pellets share a hexagonal cross-section unique to the species.
When you see it: Year-round in the Southeast, Gulf, and coastal California.
What it tells you: A drywood colony is inside the wood immediately above the pellet pile. Sweep it up; a fresh pile within a week confirms activity.

Advanced signs — colonies past three years

Blistered or bubbled paint that isn't from water

Why it appears: Workers eat with the grain and leave a paper-thin outer layer that flexes with humidity, lifting the paint film.
When you see it: Often noticed after heating or AC starts and humidity shifts.
What it tells you: A gallery has reached the drywall face — treatment now requires opening the cavity, not just spraying the surface.

Hollow-sounding trim, jambs, or subfloor

Why it appears: Continuous galleries remove the wood's core density; only a shell remains to carry sound.
When you see it: Any time — tap along suspect areas with a screwdriver handle.
What it tells you: Damage is structural. Replace-and-treat is usually cheaper than repeat spot treatments at this point.

Doors and windows that stick without a weather change

Why it appears: Moisture inside active galleries expands wood by 3–5%, which is enough to close a normal reveal.
When you see it: Progressive over weeks, not sudden.
What it tells you: Colony is mature and drawing moisture from soil, plumbing, or an unseen leak nearby.

Signs of the three US termite groups compared

Attribute	Subterranean	Drywood
Contact with soil	Required	Not required
Mud tubes	Yes — diagnostic sign	Never
Frass pellets	Rare (used as tube material)	Yes — six-sided
Swarm season	Spring, daytime	Late summer/fall, dusk
Typical entry point	Sill plate, plumbing penetrations	Attic vents, eaves, exposed rafters
Treatment	Soil termiticide or in-ground baits	Localized foam, heat, or fumigation

Signs that get misread

Sawdust piles under wood trim mean termites.

Sawdust with visible fibers is carpenter-ant frass — termites produce compact six-sided pellets, not fibrous shavings.

Both insects push waste out of galleries, but only ants cut wood mechanically.

Winged insects inside always mean termites.

Flying ants also swarm indoors. Termite wings are equal length and colorless; ant wings are unequal and often smoky.

Painted or sealed wood cannot be attacked.

Paint prevents surface entry, but any crack, screw hole, or unsealed end grain is a normal entry point.

What to do next

How many of the signs above did you find?

If: One early sign, no structural changes
Schedule an inspection within two weeks. Photograph what you found so the inspector can compare on arrival.
Ask specifically about moisture readings at foundation contact points.
If: Two or more signs, or any advanced sign
Treat as an active colony. Do not disturb mud tubes or wood — you will destroy the evidence the inspector needs.
Get a same-week inspection and request written species identification before any bid.
If: Swarmers indoors right now
A mature colony is inside the structure. Capture 5–10 swarmers in a plastic bag for species ID.
Call for emergency inspection — the swarm proves the colony is at least 3–5 years old.

Why DIY termite treatment usually fails

Retail termiticides reach only what you can see. A subterranean colony extends 20–40 feet from the visible activity and the queen sits at the far end. Killing surface workers slows nothing — the colony replaces them in weeks. Professional termite treatment works because it either treats the soil the colony must cross or uses baits the workers carry back to the queen. If you want to size the likely cost before scheduling, run the treatment estimator.

Questions this raises

How quickly can termites damage a home once signs appear?

Once mud tubes or blistered paint are visible, the colony is typically 3+ years old. Structural weakening is measurable within another 12–24 months if untreated.

Do abandoned mud tubes still matter?

Yes. They prove a colony was active within the last year and used that exact route — new tubes almost always reappear within a few feet.

Is frass dangerous to breathe?

The pellets themselves are not toxic, but the wood dust can trigger asthma. More importantly, a fresh pile means an active colony is directly above it.

Can termites be present without any visible signs at all?

Yes for the first 12–18 months. This is why annual professional inspections use moisture meters and thermal imaging, which detect galleries months before surface evidence.

Are termite swarmers the same as flying ants?

No — termite wings are all the same length and their waist is thick and straight; flying ants have a pinched waist and wings of two different lengths.

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