Dampwood termites and drywood termites differ in almost every way that matters to a homeowner: the wood they attack, the moisture they need, the signs they leave behind, and how you get rid of them. The single biggest distinction is water. Dampwood termites require wood with high moisture content, while drywood termites thrive in sound, dry wood with no ground or water contact at all. Knowing which type you’re dealing with changes your entire approach to treatment.
Size and Appearance
Dampwood termites are noticeably larger than drywood termites. Dampwood swarmers (the winged reproductive adults that fly out to start new colonies) can reach three-quarters of an inch to over an inch in length, including wings. Drywood swarmers are smaller, typically around half an inch. Both types swarm during warmer months, but dampwood termites are strongly attracted to lights at night, which is one way to tell them apart during a swarm event.
Dampwood termite soldiers have large, elongated heads with prominent mandibles, proportional to their bigger body size. Drywood termite soldiers are smaller overall, with rounded heads. Workers of both species are pale and soft-bodied, making them hard to distinguish without magnification, but the size difference is usually obvious when you see them side by side.
Where Each Type Lives
Dampwood termites are found primarily along the Pacific Coast, from British Columbia down through California, and in parts of the Southeast, particularly Florida. They colonize wood that stays consistently wet: fallen logs, tree stumps, fence posts sitting in soil, and any structural lumber that has absorbed moisture from leaks, poor drainage, or ground contact.
Drywood termites are most common in southern coastal states, including California, Arizona, Texas, Florida, and the Carolinas. Unlike dampwood species, they don’t need any soil or external moisture source. They fly directly into dry, exposed wood and establish colonies inside it. Attic framing, window frames, door headers, hardwood floors, and even furniture are all fair game. This makes them harder to detect early because they can colonize wood high above grade, far from any obvious moisture problem.
Moisture: The Key Difference
Dampwood termites cannot survive in dry wood. They need wood with consistently elevated moisture content, which in practice means wood that is decaying, waterlogged, or in direct contact with damp soil. If the wood dries out, the colony dies. This dependency on moisture is both what defines them and what makes them relatively straightforward to control.
Drywood termites extract all the water they need from the wood they eat and from metabolic processes inside their bodies. They produce extremely dry, hard fecal pellets precisely because they’re so efficient at conserving moisture internally. A piece of kiln-dried lumber in a well-ventilated attic is perfectly suitable habitat for a drywood colony.
How to Tell Them Apart by Their Droppings
Frass (termite droppings) is often the first visible sign of an infestation, and the two types produce distinctly different pellets.
Drywood termite frass pellets are tiny, no larger than about 0.04 inches long. They’re oval-shaped with six concave sides and rounded ends, giving them a distinctive hexagonal cross-section when viewed under magnification. To the naked eye, they look like coarse sand, coffee grounds, or fine sawdust. They’re very hard and dry. Drywood termites push these pellets out of the wood through small “kick-out holes” they chew into the surface. You’ll typically find little piles of frass on floors beneath infested wood, on windowsills, along baseboards, or on porches. The kick-out holes themselves are tiny, pin-sized openings that are easy to miss.
Dampwood termite frass is different. Their pellets are elongated and rounded at both ends, sometimes described as football-shaped. Critically, they lack the six distinct ridges that make drywood pellets so identifiable. Dampwood termites also tend to plaster their droppings against the walls of their galleries or use them mixed with partially digested wood to seal off tunnels, so you’re less likely to find neat piles on the floor. The frass is often softer and more irregular because of the higher moisture environment.
Damage Patterns Inside the Wood
When you cut into wood damaged by dampwood termites, the galleries (tunnels) tend to be large, smooth-walled, and oriented along the wood grain. The wood around the galleries is typically soft and visibly decayed because moisture was already degrading it before or during the infestation. You may see a mix of frass and debris packed inside the tunnels.
Drywood termite galleries cut across the grain as well as along it, creating broad, irregular chambers connected by smaller tunnels. The wood between galleries can still feel firm because it wasn’t moisture-damaged to begin with. Inside the chambers, you’ll often find loose piles of the characteristic hexagonal pellets. The overall effect is wood that looks hollowed out in an uneven pattern, sometimes with a thin, intact surface layer that conceals extensive damage underneath.
Treatment for Dampwood Termites
Because dampwood termites depend entirely on wet wood, treatment centers on eliminating moisture rather than applying chemicals. Fix leaking pipes and roofs. Make sure downspouts carry water well away from the foundation. Clear shrubbery that blocks airflow through foundation vents. Remove any wood-to-soil contact around your home, including firewood stacks, tree stumps, scrap lumber, and improperly graded planter boxes (keep planters at least four inches away from exterior walls).
Once you’ve addressed the moisture source, replace any rotted or damaged wood. Small pieces containing live termites can be soaked in soapy water to kill the insects. Larger debris can go to a landfill. If the colony has reached structural wood, heat treatment is an effective non-chemical option: the infested area is tented and heated with propane heaters until the interior of the wood reaches 130°F, then held at that temperature for about 90 minutes. The entire process typically takes less than eight hours.
In most cases, if you solve the water problem, you solve the dampwood termite problem. These colonies don’t persist in dry structures.
Treatment for Drywood Termites
Drywood termites are harder to eliminate because they don’t need an external condition you can simply remove. Treatment options fall into two categories: localized and whole-structure.
Localized treatments work when you can pinpoint the infested area. Options include injecting insecticidal dust or foam directly into kick-out holes and gallery openings, or using targeted heat treatment on a specific wall section or piece of furniture. Localized approaches are less disruptive and less expensive, but they only work if you’ve identified all the infestation sites, which is notoriously difficult with drywood termites because multiple colonies can exist in different parts of the same structure.
Whole-structure fumigation is the most reliable option for widespread or hard-to-locate drywood infestations. The entire building is sealed under a tent, and a penetrating gas fills every void and cavity in the structure. You’ll need to vacate the home for two to three days, remove food, medications, and plants, and arrange for pets to stay elsewhere. It’s expensive and inconvenient, but it reaches colonies hidden inside walls, roof framing, and other inaccessible areas that localized treatments can miss.
Which One Is Worse for Your Home?
Subterranean termites cause the most structural damage nationwide, but between these two types, drywood termites are generally the bigger threat to homes. They infest sound structural wood, they’re difficult to detect until damage is advanced, and they can’t be controlled simply by fixing a leak. Multiple colonies can establish independently throughout a structure, making comprehensive treatment essential.
Dampwood termites, while capable of significant damage, are more of a symptom than a standalone problem. Their presence almost always signals a moisture issue that’s already degrading your wood. Fix the moisture and the termites lose their habitat. If you find dampwood termites in your home, the real concern is often the water damage that invited them in the first place.