Signs of Termites: Early Detection Guide

Termites cause an estimated $5 billion in property damage annually in the United States — more than all natural disasters combined. The worst part: most termite damage isn’t covered by homeowners insurance, because insurers classify it as a preventable maintenance issue.

The good news is that catching termites early — before they’ve had years to excavate the wood inside your walls — significantly limits the damage and cost. Here’s what to look for.

The Two Most Common Termite Types

Understanding which type of termite you’re dealing with determines what signs you’ll find and how they’re treated.

Subterranean Termites

The most destructive and most common type in the U.S. They live underground in large colonies (100,000 to 1 million workers) and travel through mud tubes to reach wood food sources above ground. Found in every state except Alaska.

Species of note:

Eastern subterranean termite — most common across the eastern U.S.
Formosan subterranean termite — particularly aggressive, originally from Asia, now established across the Southeast and Hawaii. Colonies can exceed 1 million workers.
Western subterranean termite — primary species in the West

Drywood Termites

Live inside the wood they eat — no soil contact required. Found primarily in coastal areas of the Southeast, Gulf Coast, and Southwest California. Colonies are much smaller than subterranean species (typically 2,500–10,000). Treatment is different: fumigation is often required rather than soil treatment.

8 Signs of a Termite Infestation

1. Mud Tubes

This is the most definitive sign of subterranean termites. Mud tubes (also called shelter tubes or tunnels) are narrow, pencil-width tunnels made from soil, wood particles, and saliva. They allow termites to travel from soil to wood while maintaining the moisture and darkness they require.

Where to look:

Along the exterior foundation of your home
On interior basement walls and crawl space walls
Along floor joists in the crawl space
On concrete piers supporting the structure
Around plumbing pipes entering through the slab

The active tube test: Break a section of mud tube. If it’s repaired within a day or two, the colony is active. An unrepaired tube indicates abandoned activity (though doesn’t mean termites have left the building).

2. Swarmer Termites or Discarded Wings

Termite swarmers are winged reproductives that leave the colony in large numbers during spring (primarily) to mate and establish new colonies. Swarms typically last 30–60 minutes and occur on warm days after rain.

What you’ll see:

Large numbers of winged insects emerging from the soil, walls, or wood near the foundation
Or: piles of discarded wings near windowsills, doorways, and light sources (swarmers shed their wings immediately after mating)

Termite swarmers vs. flying ants:

Feature	Termite Swarmer	Flying Ant
Body shape	Straight/no waist	Pinched waist
Wings	Both pairs equal length	Front wings longer
Antennae	Straight, beaded	Bent/elbowed
Color	Dark brown/black	Black, brown, or reddish

3. Hollow-Sounding Wood

Termites eat wood from the inside out, leaving a thin outer shell intact. Tap along baseboards, window sills, door frames, and wood structural elements with a screwdriver handle. Wood that sounds hollow rather than solid may have been compromised.

Follow up with a probe: press a screwdriver tip into wood where you suspect damage. If the wood gives way or the tip punches through easily, termite damage is likely.

4. Frass (Drywood Termite Feces)

Drywood termites push their feces out of the wood through small “kick-out holes.” Frass looks like tiny pellets, roughly hexagonal in shape, about 1mm long. Often found in small piles resembling sawdust or coffee grounds.

Where to find frass:

On windowsills
On countertops beneath wooden cabinets
In closets with wood shelving
In attics

Note: subterranean termites incorporate their frass into their tunnels and don’t produce visible piles.

5. Paint Bubbling or Wallpaper Blistering

Termites within walls create moisture and heat as they eat. This can cause paint to blister or bubble, or wallpaper to bubble and separate from the wall surface — even without water damage.

If you find blistering or bubbling paint on interior walls or window frames without an obvious moisture source, termites are a possibility worth investigating.

6. Tight-Fitting Doors and Windows

As termites eat wood and produce moisture, wood can warp. Doors or windows that suddenly become stiff, hard to open, or won’t close properly — particularly along the top of the door frame — may indicate termite activity in the surrounding wood.

7. Visible Wood Damage

In advanced infestations, visible damage may appear:

Honeycombed or layered interior damage in wood (following the soft grain)
Wood that crumbles when pressed
Exposed tunnels in damaged wood

8. Termite-Damaged Wood During Renovation

Many termite infestations are first discovered during renovation or repair work — when walls are opened or floors removed, revealing damage that wasn’t visible from the outside.

Where to Inspect for Termites

Exterior inspection:

Foundation perimeter (mud tubes, termite damage at wood-soil contact)
Garage door frames (wood-to-concrete transition)
Wooden deck posts and ledger boards
Tree stumps and wood debris near the foundation
Mulch against the foundation

Interior inspection:

Crawl space (inspect all exposed wood, concrete piers, and moisture)
Basement foundation walls
Basement and ground floor door frames and window frames
Wood floor areas near exterior walls

Tools for Home Inspection

Flashlight — bright, for dark crawl space inspection
Screwdriver — for probing and tapping
Moisture meter — high moisture in wood indicates potential termite activity (and conditions that attract them)
Magnifying glass — for inspecting suspected frass and swarmers

When to Call a Professional

If you find any of the signs above, contact a licensed termite inspector. Termite control is one area where professional treatment is almost always the right call — not because you can’t identify the problem, but because:

Effective treatment (liquid soil treatment, bait systems, or fumigation) requires professional equipment and licensed product access
Inadequate treatment allows the infestation to continue causing damage
Many pest control companies offer free termite inspections

A professional will:

Confirm the species
Assess the extent of existing damage
Recommend appropriate treatment (liquid, bait system, or fumigation)
Provide documentation for insurance or real estate disclosures

Get a Free Termite Inspection

Don’t wait — termites cause extensive, expensive damage before they’re noticed. Most reputable pest control companies offer free termite inspections.

Annual termite inspections are recommended in high-risk areas, including all of the Southeast, Gulf Coast, and Mid-Atlantic states.

Prevention Checklist

Eliminate wood-to-soil contact around the foundation
Remove wood debris, stumps, and mulch from within 12 inches of the foundation
Fix plumbing and roof leaks promptly (moisture attracts termites)
Ensure adequate ventilation in crawl spaces
Store firewood off the ground and away from the house
Seal cracks in the foundation
Schedule annual termite inspections in high-risk regions

Bottom Line

Most termite infestations go undetected for 3–5 years before significant damage is apparent. Knowing what to look for — mud tubes, swarmers, hollow wood, frass, and subtle signs like tight doors and bubbling paint — gives you the best chance of catching an infestation early. If you find evidence of termites, contact a licensed pest control company for a professional assessment. The cost of annual inspections is a fraction of the cost of repairing structural termite damage.