Subterranean termites live underground and need soil contact to survive, while drywood termites nest directly inside the wood they eat. The two species differ in appearance, behavior, damage patterns, and treatment. Knowing which one you’re dealing with helps you communicate clearly with pest control professionals and choose the right solution faster.
You spot a thin mud tube snaking up your basement wall. Or maybe a pile of tiny, sand-like pellets on your windowsill. Either way, something is eating your home—and not knowing what it is can cost you thousands of dollars in misdirected treatments.
Termites cause an estimated $5 billion in property damage across the United States every year, according to the National Pest Management Association (NPMA). The damage rarely happens overnight. These insects work silently, often for months or years before a homeowner notices anything wrong. By that point, structural timber, flooring, and wall cavities may already be compromised.
Two species account for the vast majority of infestations in American homes: subterranean termites and drywood termites. They share a taste for cellulose—the organic compound found in wood—but that’s roughly where the similarities end. Their biology, nesting habits, warning signs, and treatments are distinct enough that professionals approach them very differently.
This guide breaks down everything you need to know about both species: how to tell them apart, what kind of damage each one causes, and which treatment works for which type. By the end, you’ll be able to describe your problem accurately when you call for help—and that clarity alone can save time, money, and a lot of structural headache.
What Are Subterranean Termites?
Subterranean termites are the most destructive and most widespread termite species in the United States. They’re found in every state except Alaska. Species like Reticulitermes flavipes (the Eastern subterranean termite) and Coptotermes formosanus (the Formosan termite) fall under this category.
True to their name, subterranean termites live underground. They build their colonies in the soil, sometimes housing millions of individual insects, and travel up into wooden structures to feed. Because they’re cold-blooded and need moisture to survive, they rely on the earth to regulate both temperature and humidity.
How Do Subterranean Termites Enter a Home?
Subterranean termites access your home from the ground up. They build pencil-thin mud tubes—constructed from soil, wood particles, and saliva—along foundation walls, concrete blocks, and piers. These tubes serve a dual purpose: they protect the termites from predators and prevent them from drying out during their above-ground commute.
Entry points typically include:
- Cracks in concrete foundations
- Gaps where plumbing pipes meet walls
- Wooden elements in direct contact with soil
- Expansion joints in slab foundations
What Does Subterranean Termite Damage Look Like?
Subterranean termites eat along the grain of the wood, hollowing it out from the inside while leaving a thin outer layer intact. Tap on suspected timber and it may sound hollow. Press on it and the surface might buckle or cave in entirely.
You may also notice:
- Mud tubes running up foundation walls or over concrete
- Sagging floors or doors that suddenly won’t close properly
- Blistered or bubbled paint that resembles water damage
- Swarmer wings near windowsills in spring
What Are Drywood Termites?
Drywood termites are a different problem entirely. Instead of nesting underground, they establish colonies inside dry wood—no soil contact required. They’re most common in warm coastal states like California, Florida, Texas, Hawaii, and states across the Southeast.
Drywood termite colonies are far smaller than subterranean ones, typically numbering a few thousand rather than millions. Because of their small colony size, they cause damage more slowly. But that slower timeline also makes them harder to detect.
How Do Drywood Termites Enter a Home?
Drywood termites don’t need a ground-level entry point. Winged reproductive termites (called alates or swarmers) fly through the air and land on exposed wood—roof eaves, window frames, door frames, attic beams—where they shed their wings, mate, and start a new colony.
Common entry points include:
- Unfinished or exposed wood on the exterior of the home
- Attic vents and roof joints
- Wood furniture or antiques brought inside the home
- Gaps in wood siding and trim
What Does Drywood Termite Damage Look Like?
Unlike subterranean termites, drywood termites seal themselves inside the wood and create smooth, clean galleries that cut across the wood grain. One of their most distinctive signs is frass—tiny, hard, six-sided fecal pellets that the termites kick out of small kick-out holes in infested wood.
Watch for:
- Small piles of frass (resembling coarse sawdust or coffee grounds) beneath wooden furniture or on windowsills
- Tiny kick-out holes in wood surfaces
- Isolated areas of damage in furniture, window frames, or structural beams
- Discarded wings near light fixtures
Subterranean vs. Drywood Termites: A Side-by-Side Comparison
|
Feature |
Subterranean Termites |
Drywood Termites |
|---|---|---|
|
Habitat |
Underground colonies, soil-dependent |
Directly inside dry wood |
|
Moisture needs |
High—need constant moisture |
Low—thrive in dry conditions |
|
Colony size |
Hundreds of thousands to millions |
Hundreds to a few thousand |
|
Entry point |
Ground level, foundation, soil contact |
Above ground, exposed wood surfaces |
|
Damage pattern |
Along wood grain, hollow interior |
Across wood grain, smooth galleries |
|
Key warning sign |
Mud tubes on walls or foundation |
Frass (fecal pellets) near wood |
|
Swarm season |
Spring (most species) |
Late summer to fall |
|
Geographic range |
All 49 continental US states |
Coastal and southern states |
|
Spread speed |
Fast—large colonies consume quickly |
Slower—smaller colonies |
How Do You Identify Which Termite Is in Your Home?
Before calling a pest control company, look for these distinguishing clues:
Check for mud tubes. If you find pencil-thin brown tubes running from the ground up a wall or foundation, you’re dealing with subterranean termites. Drywood termites do not produce mud tubes.
Look for frass. Small piles of tiny, pellet-shaped droppings near wood surfaces are a hallmark of drywood termites. Subterranean termite frass is mixed with soil and rarely visible in clean piles.
Consider your location. If you live in a northern inland state, drywood termites are unlikely. If you’re in Florida, Southern California, or Hawaii, drywood termites are a serious possibility.
Note where the damage is. Damage starting at or near the ground often points to subterranean termites. Damage isolated to upper-floor furniture, attic wood, or window frames suggests drywood termites.
Look for swarmers. Both species produce winged reproductives. Subterranean termite swarmers are typically black or dark brown with equal-length wings. Drywood termite swarmers tend to be reddish-brown and slightly larger.
What Treatment Does Each Termite Type Require?
Treatment is where the differences between these two species become most consequential. Using the wrong method wastes money and leaves the infestation active.
How Are Subterranean Termites Treated?
Because subterranean termites live in the soil and travel up into structures, treatment targets the ground itself.
Liquid soil treatments (termiticides): A licensed pest control professional digs a trench around the home’s foundation and applies a liquid termiticide. Products containing fipronil or imidacloprid are commonly used. This creates a chemical barrier that kills termites as they pass through.
Bait systems: Stations containing slow-acting toxic bait are placed in the soil around the perimeter of the home. Worker termites carry the bait back to the colony, gradually eliminating it. Bait systems like the Sentricon System are widely used for long-term monitoring and control.
Borate treatments: Applied directly to wood, borate-based products like Tim-bor kill termites that ingest or contact the treated surface. Borates are often used as a preventive measure during new construction.
How Are Drywood Termites Treated?
Drywood termite treatment depends on whether the infestation is localized or widespread throughout the structure.
Whole-structure fumigation (tenting): For severe or wide-ranging drywood termite infestations, tent fumigation is the gold standard. The entire structure is sealed with a tent, and sulfuryl fluoride gas is introduced. All insects inside the structure are killed. The process typically takes 24–72 hours.
Spot treatments: When the infestation is localized to a single piece of furniture or a small area of wood, spot treatments may be sufficient. Methods include:
- Electro-gun (electrocution): Delivers a controlled electrical charge into infested wood
- Microwave treatment: Heat applied to a targeted area kills termites without chemicals
- Direct wood injection: Termiticides injected directly into kick-out holes and galleries
Heat treatment: The entire structure—or a specific room—is raised to approximately 120°F (49°C) for several hours. At this temperature, termites at all life stages are killed. No chemicals are required, making this a popular option for those seeking a chemical-free approach.
Which Treatment Should You Choose?
The right treatment depends on the termite species, the extent of the infestation, and the structure of your home.
- Choose liquid soil treatment or bait systems if you have subterranean termites with widespread or recurring activity around the foundation.
- Choose whole-structure fumigation if you have drywood termites spread throughout multiple areas or if previous spot treatments have failed.
- Choose spot treatment or heat treatment if you have a small, clearly defined drywood termite infestation in furniture or a specific wood element.
- Consult a licensed pest control professional before committing to any method. Proper species identification is the first step.
When Should You Call a Professional?
Immediately. Not next week.
Termite colonies grow. A small subterranean colony left untreated for another season can balloon in size. A localized drywood infestation in a window frame can spread to adjacent structural wood before you know it. The NPMA recommends annual termite inspections for homes in high-risk areas—and at least every two to three years for lower-risk regions.
When you call a pest control company, the information you’ve gathered matters. Tell the technician:
- Where you first noticed damage or warning signs
- Whether you found mud tubes, frass, or discarded wings
- The location of the damage (ground level vs. upper floors)
- Whether swarmers appeared inside or outside the home
That detail helps the inspector confirm the species quickly and design a treatment plan with precision.
What You Now Know—and What to Do Next
Subterranean and drywood termites are two distinct adversaries. One tunnels up from the earth; the other floats in on wings and sets up camp inside dry timber. Their damage patterns, warning signs, and treatments are different enough that confusing the two can result in wasted effort and continued destruction.
The good news: you now know what to look for. Mud tubes mean subterranean. Frass pellets mean drywood. Location, entry point, and damage pattern confirm the picture. Armed with that knowledge, you can walk into a conversation with a pest control professional, describe exactly what you’re seeing, and get to the right solution faster.
Book a professional termite inspection—especially if you live in a high-risk state or your home is more than 10 years old. The inspection itself is often free or low-cost, and the peace of mind is worth every penny.
Frequently Asked Questions
Can you have both subterranean and drywood termites in the same home at the same time?
Yes. It’s uncommon but not impossible, particularly in warm coastal states like Florida and California where both species are prevalent. A professional inspection can identify whether one or both types are present, which would require a combined treatment strategy.
How long does it take for termites to cause serious structural damage?
Subterranean termites can cause significant damage within three to five years if a mature colony goes undetected. Drywood termites cause damage more slowly, but long-term infestations spanning several years can still compromise structural integrity, particularly in attic beams and load-bearing wood.
Are drywood termites less dangerous than subterranean termites?
Drywood termites are generally slower to cause widespread damage due to their smaller colony size, but they should not be underestimated. Their ability to nest in furniture and upper-story wood makes them harder to detect, and untreated infestations can spread and weaken wood over time.
What is frass, and how is it different from sawdust?
Frass is drywood termite excrement. Unlike sawdust, frass pellets are uniform in shape—typically six-sided—and are hard and dry. Sawdust is irregular and fibrous. Finding small, sand-like piles of frass beneath wood is one of the clearest indicators of a drywood termite infestation.
Do termite treatments require you to leave your home?
It depends on the treatment type. Liquid soil treatments for subterranean termites typically don’t require occupants to vacate. Whole-structure fumigation for drywood termites requires all people, pets, and plants to leave the home for 24–72 hours until the gas dissipates to a safe level.
Is DIY termite treatment effective?
DIY products like borate sprays or retail termite baits may provide limited short-term relief for minor infestations, but they rarely eliminate an established colony. Professional-grade termiticides and treatment equipment are significantly more effective. For any confirmed infestation, a licensed pest control professional is strongly recommended.
How much does termite treatment cost?
Costs vary widely depending on the treatment type, home size, and severity of infestation. Liquid soil treatments typically range from $300 to $900. Bait systems may cost $800 to $3,000 for initial installation and annual monitoring. Whole-structure fumigation generally falls between $1,200 and $2,500 for an average-sized home, according to industry estimates.