You notice a small pile of what looks like sawdust or coffee grounds near a windowsill or along a baseboard. You sweep it up, and a few days later it’s back. You sweep it again. It comes back again. That cycle, finding and clearing a mysterious pile of fine debris that keeps reappearing in the same spot, is one of the most recognizable patterns of a drywood termite infestation.
What you’re looking at is termite frass. It’s the collective term for drywood termite droppings, and it’s one of the clearest diagnostic signs that a colony is actively feeding somewhere above or behind the surface where you found it.
Here’s what you need to know about termite frass: what it looks like, how to tell it apart from other common household debris, where to find it, and what to do when you do.
Frass is a term used in entomology for the excrement and other debris produced by insects. In the context of termites, it refers specifically to the dry, pellet-shaped droppings that drywood termites push out of their galleries through small openings called kick-out holes.
Unlike subterranean termites, which incorporate their waste into the mud tubes they build, drywood termites keep their gallery system clean. They excavate small holes in the wood surface and use them to expel frass from the colony. This keeps the interior of the gallery dry and sanitary, which is important for a species that lives entirely inside the wood it consumes.
The result is a neat little pile of pellets directly below each kick-out hole. The pile accumulates over time as the colony feeds, which is why you’ll keep finding it in the same location if you clear it away without addressing the infestation above.
Termite frass has a distinctive appearance once you know what to look for. The individual pellets are tiny, roughly the size of a grain of sand or a poppy seed. They’re oblong or elongated with six slightly flattened sides, giving them a shape that’s been described as resembling a grain of rice at a much smaller scale.
The color of frass varies depending on the type of wood the termites are eating. It can range from very light tan or cream when they’re feeding on pine or other light-colored softwood, to medium brown when feeding on oak or similar hardwoods, to dark brown or almost black when feeding on darker stained wood. This variability means that frass from the same species can look quite different from one home to the next.
Sawdust is irregular in shape, flaky, and inconsistent in size. The particles come in a range of sizes from fine powder to visible wood chips. Termite frass, by contrast, is remarkably uniform. Each pellet is very close to the same size and the same elongated shape. If you look at a pile under magnification, the regularity is obvious.
Sawdust also doesn’t reappear after you clean it up unless you’re actively doing woodworking in the same spot. Frass comes back because the colony above the kick-out hole is still actively feeding and producing waste. That repetition is a key diagnostic clue.
Ant droppings tend to be smaller, rounder, and less uniform than termite frass. Ants also tend to deposit waste in a midden pile at a specific location rather than through a hole in a wood surface. If the pile you’re finding is coming from a distinct small hole in a wood surface, it’s much more likely to be termite frass than anything an ant colony would produce.
General household dust settles in a flat, diffuse layer rather than accumulating in a concentrated pile. Frass piles are compact, usually no larger than a dime or a nickel in circumference, and they build up relatively quickly compared to the gradual settling of dust. The location also matters: frass piles appear directly below kick-out holes in wood surfaces, not randomly across a shelf or floor.
Because drywood termites live inside wood, frass piles appear wherever they’ve established a colony and created kick-out holes. The most common locations in Southern California homes include:
Window frames are a frequent entry point for drywood termite swarmers and a common location for colony establishment. The wood in window frames is often exposed to sunlight and can have small cracks or joints that make access easy. Check the sill directly below the frame for fine pellet accumulation.
Interior trim wood is another common target. Frass piles along baseboards often look like a thin line of debris settled against the wall. Door frames, especially the header above the door, are worth checking if you’ve noticed any sticking or warping alongside the suspicious debris.
The attic is one of the most common locations for drywood termite colonies in Southern California homes because it offers exactly what the species needs: dry, warm, undisturbed wood. Frass from attic colonies can fall through gaps in the ceiling onto insulation below, or accumulate on top of attic flooring boards. If you access your attic and find pellet accumulation on any horizontal surface, treat it seriously.
Drywood termites can infest wooden furniture, particularly older or antique pieces, as well as built-in cabinetry, bookshelves, and wood paneling. Frass found on or below a piece of furniture that isn’t near an obvious structural wood source may indicate the furniture itself is infested. This is also how drywood termites get introduced into homes: through infested used furniture or reclaimed wood.
If a colony has established in the subfloor or in the underside of hardwood flooring, frass can accumulate in the seams between floor planks or appear to be coming up from below the floor surface. This is a less common presentation but worth knowing about if you’re finding unexplained debris near floor level with no obvious overhead source.
The size of the frass pile isn’t a reliable indicator of colony size on its own, because the accumulation rate depends on how recently the pile was cleared, how active the colony is at that moment, and how many kick-out holes are contributing to the pile.
What matters more is the pattern. A small pile that reappears consistently within a day or two of being swept up indicates an actively feeding colony. Multiple frass accumulation points in different areas of the same home suggest either multiple colonies or a colony that has spread through a large section of the structure.
The only reliable way to assess the actual extent of a drywood infestation is a professional inspection. A trained technician will use a combination of visual inspection, probing, and in some cases moisture detection to map where active feeding is occurring and how far the colony has spread.
The steps are simple but the order matters.
Once a drywood termite infestation is confirmed through inspection, the treatment approach depends primarily on how localized or widespread the colony has become.
When the infestation is limited to a specific, accessible section of wood, spot treatment is the least invasive and most efficient option. The technician drills small access holes into the infested wood, injects termiticide directly into the gallery system, and seals the holes after treatment. This approach eliminates the colony at the source without requiring the homeowner to vacate the property.
When frass is found in multiple locations throughout the home, or when the inspection reveals that the colony has spread into areas that can’t be fully accessed for spot treatment, whole-structure fumigation is the most thorough solution. The home is sealed under a tent and treated with a gas that penetrates all wood throughout the structure, eliminating every colony present regardless of location. It’s the only method that can guarantee complete eradication of a widespread drywood infestation.
If you’re finding small pellet piles that keep coming back, there’s a drywood termite colony above that spot and it isn’t going to stop on its own. The longer it feeds, the more wood it destroys and the more extensive the treatment and repair process becomes.
MEC Termite & Pest Control has been identifying and treating drywood termite infestations in Garden Grove and Orange County for over 27 years. Our inspections are free for residential homeowners and we’ll give you a clear, honest assessment of what we find.
Call us at 714-951-4015 or reach out online to schedule your free inspection. We’ll tell you exactly where the colony is, how far it’s spread, and what the best treatment path looks like for your home.