Drywood termites leave one of the clearest visual signatures in structural pest management: small mounds of uniform pellets beneath pinhole-sized openings. Homeowners often discover frass on baseboards, beneath exposed beams, or near window frames—sometimes mistaking it for sawdust or sand. The pellets themselves are hard, six-sided, and roughly the size of a grain of sand, with concave ends that distinguish them from wood shavings or debris from other insects. The kick-out holes above these piles are functional: worker termites periodically clear fecal matter from their tunnels to maintain clean living space, and the accumulation below signals ongoing activity.
Because drywood termites colonize above ground and do not build mud tubes, frass and kick-out holes are often the only external evidence until structural damage becomes severe. A single colony may contain a few hundred to a few thousand individuals, feeding slowly but persistently within attic framing, furniture, door jambs, or trim. According to University of California Agriculture and Natural Resources guidelines, localized infestations in accessible wood can sometimes be treated with spot fumigation or heat, while widespread activity across multiple structural members typically requires whole-structure fumigation or an alternative such as heat treatment.
You can safely collect a sample of the frass in a sealed plastic bag and photograph the kick-out holes for reference during inspection. Do not attempt to probe the wood with tools or apply over-the-counter pesticides into the holes—doing so can scatter the colony, complicate professional assessment, and void treatment warranties. Travis Gates, a licensed pest-control operator with field experience in drywood-prone regions, notes that homeowners who disturb active galleries before inspection often make it harder to map the full extent of infestation, which can lead to incomplete treatment and re-infestation in adjacent wood members.
If you are uncertain whether the material is termite frass or another wood-boring insect byproduct, a licensed termite inspection will provide species confirmation and a written report detailing all affected areas. You can also use the Termite Risk Score tool to understand how your property’s construction type, climate zone, and wood-contact conditions influence drywood termite likelihood. For broader context on how drywood species differ from subterranean and dampwood termites, see Types of Termites: Species.
What Changes the Meaning of Drywood Termite Evidence
Drywood termite frass and kick-out holes don’t carry a single interpretation. The variables that matter most are evidence age, colony size, wood moisture, treatment history, and whether you’re in an active real-estate transaction.
Fresh frass—light-colored, dry, and accumulating within days—indicates active feeding. Older frass darkens, clumps when exposed to moisture, and may sit undisturbed for months after a colony died or was treated. Kick-out holes stay visible long after activity stops, so a hole alone doesn’t confirm current infestation. The combination of fresh frass below an open hole, especially after you’ve cleared the pile and it reappears within a week, points to live colonies.
Colony maturity changes urgency. A single gallery with one kick-out hole represents a small, localized colony that may have been feeding for one to three years. Multiple kick-out holes across different rooms, attic framing, or exterior trim suggest either a larger mature colony or several independent colonies, which is common in high-pressure drywood zones like coastal Southern California, South Florida, and Hawaii. According to University of California extension guidance, drywood colonies grow slowly—adding only a few hundred termites per year—but older colonies spread through interconnected galleries that cross multiple framing members.
Wood moisture below 12 percent supports drywood termites, which extract water metabolically and don’t need soil contact. If you find frass near plumbing leaks, roof damage, or areas with elevated moisture, you may be dealing with dampwood termites or a mixed infestation, which changes treatment approach. Our termite species guide covers identification differences that affect professional recommendations.
Treatment history matters during property transactions. If the seller provides a termite report showing drywood activity treated within the past two years, new frass in the same location may indicate incomplete treatment, recolonization, or a separate untreated colony nearby. Some whole-structure fumigation contracts include limited warranties; others cover only the treated areas. Warranty language determines whether follow-up treatment costs fall to the buyer or remain the responsibility of the original service provider.
Local drywood pressure—mapped by state agriculture departments and reflected in our infestation map—affects whether isolated evidence justifies whole-structure fumigation or targeted spot treatment. In low-pressure areas, a single kick-out hole may warrant monitoring. In endemic zones, the same evidence often triggers aggressive treatment because unseen colonies are statistically likely elsewhere in the structure.
These variables don’t resolve themselves through observation. They guide the questions you ask during a licensed termite inspection, which remains the only reliable way to distinguish between cosmetic old evidence and active hidden damage.
How Drywood Termites Differ from Subterranean, Formosan, and Dampwood Species
Drywood termites live entirely inside wood—no soil contact, no mud tubes, no moisture bridges. Subterranean termites, by contrast, nest in soil and build pencil-width mud tubes up foundation walls or slab edges to reach wood. Formosan termites, a subterranean species, build larger carton nests in walls or attics when moisture is present and forage aggressively across multiple structures. Dampwood termites occupy wet, decaying wood in crawlspaces, leaky window frames, or coastal climates and rarely infest dry, sound lumber.
The visible evidence differs by species. Drywood termites push dry, sand-textured frass out of kick-out holes—small, round exit ports drilled through the wood surface. You find frass piles on windowsills, baseboards, or furniture below infested timber. Subterranean termites leave mud shelter tubes on concrete, hollow-sounding wood, and sometimes mud-packed galleries inside damaged beams; you will not see frass piles because workers carry waste back to the soil. Formosan swarmers emerge in large evening flights during late spring and early summer, often near exterior lights, and carton nests may appear as brittle, mud-like masses inside wall voids. Dampwood termites produce moist, paste-like frass and leave large exit holes in soft, water-damaged wood; infestations stay localized to the wet area unless the moisture source spreads.
Treatment implications follow biology. Drywood colonies are small—hundreds to low thousands of individuals—and confined to individual boards, furniture, or attic framing, so spot treatments, heat, or whole-structure fumigation are common options. Subterranean colonies number in the hundreds of thousands, nest underground, and require soil-applied termiticides, bait stations, or perimeter barriers that intercept foraging workers. Formosan colonies can exceed one million individuals and demand aggressive liquid treatments, baiting programs, and moisture correction; the University of Florida IFAS and NPMA both classify Formosan infestations as high-priority due to rapid damage potential. Dampwood control starts with eliminating the water source—roof leaks, plumbing failures, or ground contact—then removing infested wood; pesticide treatment is secondary to moisture repair.
If you see dry frass and kick-out holes, you are likely observing drywood activity. Mud tubes on the foundation point to subterranean termites. Large evening swarms and carton nests suggest Formosan pressure. Soft, wet wood with large exit holes indicates dampwood colonization. A licensed inspector will identify the species, map the infestation, and recommend treatment scaled to colony size, access path, and structural risk. For help assessing your property’s baseline exposure, use the Termite Risk Score tool, and review the species overview for additional identification detail.
What You Can Do Before Calling a Professional
If you’ve found frass piles or suspect kick-out holes, you can document what you see and prepare useful information for an inspector without disturbing evidence or attempting treatment yourself.
Start by photographing each frass pile and the wood surface directly above it. Use a ruler or coin in the frame for scale. Note the date, location, and whether the pile appeared suddenly or accumulated over weeks. Check whether frass is actively falling by placing a sheet of dark paper beneath the suspected kick-out hole and checking it daily for three to five days. Fresh accumulation suggests active feeding, though absence of new frass does not confirm the colony has left—drywood termites feed intermittently and may pause activity for weeks.
Inspect adjacent wood surfaces with a flashlight, looking for additional small holes, surface blisters, or hollow-sounding areas when tapped gently. Do not probe aggressively or drill test holes; you may damage sound wood or obscure evidence the inspector needs. If the suspected area is inside furniture, check joints, unfinished undersides, and drawer channels. For structural wood, note whether the frass is near windows, door frames, attic beams, or exterior trim—locations that help inspectors prioritize their search.
Gather any termite-related records you have: previous inspection reports, treatment contracts, builder warranties, or disclosure documents from your home purchase. If you’ve had other pest activity or wood-boring beetles, note those details separately. Drywood termite frass is distinct, but inspectors sometimes find overlapping issues that change the treatment approach.
Prepare a short list of questions based on what the inspector finds. Useful topics include the extent of infestation, whether the activity is localized or distributed, treatment options suited to your structure, and whether surrounding homes have reported drywood termites. Our Termite Risk Score can help you understand regional pressure and construction factors that influence long-term risk.
Understand the boundaries of self-assessment. You cannot determine colony size, confirm species identity, or rule out hidden galleries from visible frass alone. Drywood termites often occupy multiple disconnected sites within a structure, and a single frass pile may represent a small satellite group or the visible edge of a larger infestation. Even experienced inspectors use a combination of visual examination, probing, moisture meters, and sometimes thermal imaging to map activity accurately.
Do not apply pesticides, sealants, or wood treatments before the inspection. Covering kick-out holes or vacuuming frass before documentation can eliminate the evidence an inspector uses to locate the colony. If you need help distinguishing drywood termite frass from other wood-damaging insects, see our guide to signs of infestation for side-by-side comparisons and professional routing steps.
