Drywood termites are one of the most common wood-destroying pests in California, particularly along the coast and throughout Southern California. The western drywood termite (the primary species in the state) is actually native to the region, meaning it’s not an invasive problem you can eradicate from the landscape. It’s a permanent part of homeownership in much of the state. Understanding what to look for, how these termites differ from their subterranean cousins, and what your treatment options are can save you thousands of dollars in structural damage.
Where Drywood Termites Live in California
The western drywood termite is commonly found along the entire Pacific coastal region, into the Central Valley, and across the deserts of Southern California. If you live in San Diego, Los Angeles, the Bay Area, or anywhere in between, drywood termites are in your neighborhood. They’re also present at inland locations that many homeowners don’t expect, including desert communities in the Coachella Valley and parts of the Sacramento area.
Unlike subterranean termites, which nest underground and need constant moisture, drywood termites can survive in very dry conditions. They don’t need contact with soil at all. Their colonies live entirely inside the wood they’re eating, whether that’s structural lumber in your walls, a dead limb on an oak tree, a fence post, a deck, or even a piece of furniture. This is what makes them so sneaky: there’s no mud tube running up your foundation to tip you off. The entire colony is hidden inside the wood, often for years before you notice.
How to Spot an Infestation
The single most reliable sign of drywood termites is their fecal pellets, commonly called frass. These tiny pellets have a distinctive six-sided, oblong shape when viewed under magnification. To the naked eye, they look like fine dust or sand, and their color varies from light tan to dark brown depending on the type of wood the termites are eating.
Drywood termites are surprisingly tidy. They cut small “kickout holes” in the surface of the wood and push their waste pellets out through these openings. If the hole is just a few inches above a windowsill or shelf, the pellets form a small, noticeable pile. But if the kickout hole is higher up on a wall or ceiling, the pellets bounce and scatter when they land, making them easy to dismiss as ordinary dust or debris. This is why many infestations go undetected: homeowners sweep up the evidence without realizing what it is.
The other common sign is swarmers. During summer and fall, winged adult termites leave the colony during daytime hours to mate and establish new colonies. You might see them flying near windows or light sources, or you might just find their shed wings on windowsills and floors. A pile of small, translucent wings indoors almost always means a colony is active somewhere in the structure.
Drywood vs. Subterranean Termites
California has both drywood and subterranean termites, and telling them apart matters because the treatment approaches are completely different. Subterranean termites are abundant across most of the state, even at elevations above 8,000 feet. They live and breed in the soil, sometimes many feet below the surface, and they build distinctive shelter tubes made of saliva mixed with soil and wood bits to travel between their underground nest and your home. If you see mud tubes running up your foundation or along a wall, that’s a subterranean species.
The damage patterns differ too. Subterranean termites generally follow the grain of the wood, eating the softer spring growth layers and leaving behind the harder wood in a layered pattern. Drywood termites cut across the wood grain, creating a distinctive pattern of smooth chambers and tunnels, some of which are packed with their hexagonal fecal pellets. If you break open a piece of damaged wood and find small pellets inside the galleries, you’re dealing with drywood termites.
The practical difference for homeowners is this: subterranean termites are treated by targeting the soil and the connection between the ground and your structure. Drywood termites require treating the wood itself, since the colony has no soil connection to interrupt.
Treatment Options
Treatment for drywood termites falls into two broad categories: localized (spot) treatments and whole-structure fumigation. The right choice depends on how widespread the infestation is and how confident you can be that you’ve found all the colonies.
Localized Treatments
When the infestation is limited to one or a few accessible areas, spot treatments can be effective and far less disruptive than fumigation. UC IPM recommends considering nonchemical options first, including wood replacement, heat treatment, electrocution devices, and desiccants (drying agents injected into galleries). Insecticidal liquids, dusts, or foams can also be injected directly into termite galleries through small drilled holes.
Heat treatment works by raising the temperature of the infested wood to a core temperature of at least 120°F, which is lethal to all life stages of the termite. This can be done for a localized area using portable heating equipment, or for an entire structure. The advantage is that it leaves no chemical residue. The limitation is that heat must penetrate to the center of the wood, which can be difficult in thick structural members or areas with poor air circulation.
The biggest risk with any localized treatment is missing a hidden colony. Drywood termites can infest multiple locations in a structure simultaneously, and some colonies may be in wall voids or attic framing where they produce no visible frass. If you treat one spot but miss another, the infestation continues.
Whole-Structure Fumigation
When drywood termite damage is widespread or when you can’t be certain you’ve located every colony, whole-structure fumigation is often the recommended approach. This is the process Californians know well: a large tent is placed over the entire house, and a fumigant gas is released inside. The gas fills every air space in the structure, penetrating cracks, crevices, and pores in the wood to reach termites wherever they’re hiding.
The fumigant used for termite work is sulfuryl fluoride. It’s introduced as a gas that must remain contained under the tent for a sufficient period to be effective, typically one to three days depending on the size of the structure, the temperature, and the severity of the infestation. You and your family (including pets and plants) must leave the home before fumigation begins and cannot return until the gas has been cleared.
Once the tent is removed, the gas dissipates to very low levels within 24 hours. Before you’re allowed back in, the fumigator must measure sulfuryl fluoride levels and confirm they’re below 1 part per million, as required by the EPA. The gas leaves no residue on surfaces, which means it also provides no ongoing protection against future infestations. A home fumigated today can be reinfested by a new swarm next year.
Preparation for fumigation is significant. You’ll need to remove or double-bag all food, medications, and consumables. You’ll need somewhere to stay for two to three nights. And the cost typically runs several thousand dollars depending on the size of your home.
Inspections and Real Estate Transactions
In California, termite inspections are handled by companies licensed through the Structural Pest Control Board, which oversees Branch 3 licensees (wood-destroying organism inspectors). During a real estate transaction, a Wood Destroying Organism (WDO) inspection report is commonly requested by lenders or buyers, though it’s not always legally required by the state for every sale. The report categorizes findings into Section 1 (active infestations and damage requiring immediate treatment) and Section 2 (conditions that could lead to future infestation, like wood-to-soil contact or moisture issues).
These inspection reports are filed with the Structural Pest Control Board and are searchable through their WDO Property Search system, which means you can look up the termite history of a property before you buy it. If you’re purchasing a home in coastal or Southern California, checking this database is worth the few minutes it takes. A history of repeated drywood termite treatments can signal that the property is in a high-pressure area where reinfestation is likely, which should factor into your maintenance planning and budget.
Preventing Reinfestation
Because drywood termites are native to California and constantly producing new swarmers, no treatment provides permanent protection. There are, however, practical steps that reduce your risk. Sealing cracks around window frames, door frames, and eaves limits entry points for swarmers looking to start new colonies. Screening attic and crawlspace vents with fine mesh (20-gauge or smaller) blocks flying termites from accessing vulnerable wood.
If you’re building or remodeling, using pressure-treated or naturally resistant wood for exposed structural elements helps. Borate-treated wood is particularly effective, as the boron compounds are toxic to termites but remain stable in the wood long-term. Keeping an eye out for frass piles, especially on windowsills, shelves, and in garages or attics, gives you the best chance of catching a new infestation early, when a localized treatment is still an option and before the colony has had years to spread through your framing.