Termite Facts and Statistics: What California Homeowners Should Know
How much damage do termites really do, which kinds live in California, and when do they swarm? Here are the key numbers — every figure sourced, no scare tactics.
Termites cause more than $6.8 billion in U.S. property damage a year (National Pest Management Association, 2021), and the California Department of Insurance lists termites among the perils a homeowners policy generally does not cover. UC IPM ranks western subterranean termites, which nest in soil and build mud tubes, as California's most destructive termites, and the western drywood termite, which lives inside the wood, as the state's second most important termite pest. Drywood termites swarm in daylight in summer and fall; subterranean termites swarm on warm, sunny days after spring or fall rains.
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Termite marketing leans on fear, so it's worth knowing the actual numbers. Here are the statistics and facts that matter for California homeowners, with a source for every figure — compiled by a licensed WDO inspector who works these houses every week.
The key numbers at a glance
| Statistic | Figure | Source |
|---|---|---|
| Property damage caused by termites in the U.S. | More than $6.8 billion per year | National Pest Management Association |
| Covered by homeowners insurance? | Generally no — termites are listed among the perils a homeowners policy generally does not cover | California Department of Insurance residential guide |
| Main termite pests in Southern California | Western subterranean and western drywood; the invasive Formosan subterranean termite has also been confirmed in a few Southern California locations (see our Formosan page) | UC Statewide IPM Program |
| Western drywood colony size | Usually fewer than 1,000 individuals, widely dispersed, taking years to mature | UC IPM |
| Western subterranean colony size | Tens of thousands to hundreds of thousands | UC IPM |
| Queen lifespan | Can exceed a decade | Oklahoma State University Extension (reports up to 25 years) |
| Bait-station program (subterranean treatment) longevity | Ongoing while serviced — stations opened and re-baited each year | ExterMetro annual program terms |
| Residual protection after fumigation | None — it eliminates what's present, not what comes next | UC IPM Pest Notes: Drywood Termites (fumigants leave no residual) |
Which termites live in the San Gabriel Valley
Two types are the main structural pests here: UC IPM ranks subterranean termites as California's most destructive and the western drywood termite as the state's second most important termite pest. Western drywood termites live entirely inside wood — eaves, attics, framing — and are the classic problem in our older housing stock; they announce themselves with six-sided frass pellets.
Western subterranean termites nest in the soil and build mud tubes up into the structure; they field far larger colonies, which is why they're considered the more destructive of the two. (A third type, the dampwood termite, needs chronically wet wood and turns up mainly where there's a moisture problem.)
When California termites swarm
Swarm timing here differs from the East Coast pattern you'll read on national sites. In Southern California, drywood swarmers fly during daylight in summer and fall, while subterranean swarmers typically fly on warm, sunny days after a soaking rain, in spring or fall, with spring the peak, according to UC IPM. Piles of identical shed wings indoors are the tell either way; here's how to tell swarmers from flying ants.
What the damage numbers mean in practice
Nearly seven billion dollars a year sounds abstract until you remember two things: the damage is almost never covered by insurance, and it accumulates silently — a colony can feed for years before the first visible sign. That combination is why periodic inspections are the cheapest protection there is: the difference between a localized spot treatment and structural repair is usually just time.
Sources
- National Pest Management Association: Five Termite Species All Homeowners Should Be Aware Of
- UC IPM Pest Notes: Drywood Termites (University of California)
- UC IPM Pest Notes: Subterranean and Other Termites (University of California)
- California Structural Pest Control Board
- California Department of Insurance: Residential Insurance Guide
- Oklahoma State University Extension: Subterranean Termite (Reticulitermes sp.)
- UC IPM “Green Bulletin”, Fall 2023
Local seasonality reflects twelve years of San Gabriel Valley field work.
Quick Answers
Quick Answers.
How much damage do termites cause each year?
The National Pest Management Association puts termite property damage at more than $6.8 billion a year in the United States (2021 figure), and the California Department of Insurance lists termites among the perils a standard homeowners policy generally does not cover.
What kinds of termites are in California?
UC IPM counts at least 23 termite species in California, but two main types do the structural damage: western subterranean termites, which nest in soil and build mud tubes into structures, and western drywood termites, which live inside the wood itself. Dampwood termites appear where wood stays chronically wet, and the invasive Formosan subterranean termite has been confirmed in a few Southern California locations.
When is termite season in Southern California?
Drywood termites swarm in daylight in summer and fall. Subterranean termites swarm on warm, sunny days after a soaking rain in spring or fall, and UC IPM calls spring the peak. Damage happens year-round; swarms are just when they're visible.
How big does a termite colony get?
Drywood colonies stay small — UC IPM puts them at usually fewer than 1,000 individuals — widely dispersed and slow to mature. Subterranean colonies range from tens of thousands to hundreds of thousands, which is why they're considered the more destructive type.
How reliable are these numbers?
Each figure is attributed on the page: the national damage figure comes from the National Pest Management Association (2021), the insurance answer from the California Department of Insurance's residential insurance guide, species, colony-size, swarm-season and queen-lifespan facts from the UC Statewide IPM Program and Oklahoma State University Extension, and the bait-station row from our own annual program terms.
Can one house have more than one termite colony?
Yes. UC IPM notes that several colonies of the same species, or of different species, can infest one building, and a home with a 2,400-square-foot footprint could have several subterranean colonies foraging around it. In a two-year University of California study at homes in the Bay Area and greater Los Angeles, DNA testing found three to five separate colonies at many of the sites, and one property had 15.
Are termites active in winter in Southern California?
Yes. UC IPM says subterranean termites in California can forage year-round, with the intensity changing by season. Its Pest Note describes statewide foraging as lightest from November to February, while a 2023 UC IPM newsletter notes that western subterranean termites in Southern California have been observed foraging near the surface mostly during the winter months. Drywood colonies live deep inside the wood they infest, so they are rarely seen until they swarm. Swarms are seasonal; feeding is not.
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About the Author
Joshua A. Westad is the owner and licensed operator of ExterMetro Termite and Pest Control in Arcadia, CA. He holds California SPCB Company Registration #8828 (Branch 2 & 3), is a licensed WDO inspector, and has worked San Gabriel Valley homes and businesses for over twelve years — hands-on in the field on every kind of job the valley throws at him.
Think you just found termite evidence?
Bag a few wings or pellets, snap a photo, and text it to (626) 409-1584 — quotes from photos are free, and your job stays under licensed ExterMetro oversight from inspection through follow-up.