Termites in the San Gabriel Valley
Termites work silently for years. Here's how to identify the two types that matter in the SGV and the signs they leave behind.
- Drywood: live inside wood, leave pellet piles
- Subterranean: live in soil, build mud tubes
- Swarmers: equal-length wings, straight body (not ants)
- Shed wing piles on sills signal a swarm
- Hollow-sounding or blistered wood
What are termites?
Termites are social insects that feed on cellulose, mainly wood, and live in colonies divided into workers, soldiers and reproductives, according to the University of California. A colony can be as small as a newly paired king and queen or as large as hundreds of thousands, and nearly all of it stays hidden inside wood or soil. The termites most people ever see are the swarmers, winged reproductives that leave a mature colony to start new ones.
What they look like
Two kinds of termite matter in the San Gabriel Valley. Drywood termites live entirely inside dry wood — attics, eaves, framing and furniture — and need no contact with soil. Subterranean termites live in the soil and build mud tubes up to reach wood. The termites most homeowners actually see are the swarmers (winged reproductives).
Swarmers are routinely mistaken for flying ants. The tells: termites have straight, bead-like antennae, a thick uniform waist, and two pairs of equal-length wings — ants have elbowed antennae, a pinched waist and unequal wings. Here's the full swarmer-vs-flying-ant check.
Drywood vs. subterranean termites
Where they live
Drywood termites infest sound, dry wood above ground and can start a colony anywhere a swarmer lands and bores in — which is why drywood damage often shows up in attics, window and door frames, eaves and even wood furniture.
Subterranean termites nest in the soil and travel through pencil-width mud tubes on foundations, piers and crawl-space walls to reach wood. They're tied to moisture, so leaks, poor drainage and earth-to-wood contact around SGV homes raise the risk.
Signs of termites
The early warning most people catch is a pile of discarded wings on a windowsill or floor after a swarm, or small piles of pellets (drywood frass) that look like coarse sand or coffee grounds beneath infested wood. Subterranean activity shows as mud tubes on the foundation.
Later signs include wood that sounds hollow when tapped, blistered or rippled paint, and tight-fitting or sagging floors and trim. Our guide to the signs of termites walks through each one.
Types of termites in Southern California
Southern California has four termites worth knowing: western drywood and western subterranean termites do nearly all the damage, dampwood termites show up where wood stays wet, and Formosan subterranean termites have been confirmed in a few pockets. The University of California ranks the subterranean termite as the state’s most important termite pest and the western drywood termite as the second.
| Termite | Where it lives | The sign | When it swarms | Usual treatment |
|---|---|---|---|---|
| Western drywood | Inside dry, sound wood above ground: eaves, attics, framing, furniture | Six-sided pellets under kickout holes smaller than 2 mm | Daytime, summer and fall | Localized treatment, or fumigation when widespread |
| Western subterranean | In the soil, reaching wood through mud tubes | Pencil-width mud tubes on foundations and piers | Warm, sunny days after fall or spring rains | Bait stations plus targeted non-repellent soil treatment |
| Dampwood | Wet, decaying wood; most often in cool, humid coastal areas | Damage confined to chronically wet wood | Toward lights after dark | Fix the moisture and replace the wood |
| Desert subterranean | The Sonoran Desert of southeastern California, not the SGV | Mud tubes in desert areas | Evening, attracted to lights | As for subterranean termites |
| Formosan subterranean | Soil, or wet aerial nests; confirmed in a few Southern California pockets | Evening swarms at lights | Dusk, late May to early August | Report to UC Riverside; bait and soil treatment, aerial nests treated directly |
How termites are treated: localized, fumigation, bait and soil
How termites are treated depends on which termite it is and how far the activity spreads, which is why the inspection comes first. Warranties cover retreatment of the termites, not repair of damage.
| Treatment | For | What it involves | Trade-off |
|---|---|---|---|
| Localized treatment | Drywood activity an inspection can find and reach | Small drilled holes, product placed directly into the galleries, holes patched; one visit, you stay home | Treats what can be found; we carry a two-year retreatment warranty on it |
| Fumigation | Widespread or hidden drywood activity | The structure is tented and filled with sulfuryl fluoride, aerated, and cleared by air readings; two to three nights out | Reaches every drywood colony in the house, leaves no residual protection, does nothing to subterranean termites |
| Bait stations | Subterranean termites | In-ground stations around the house; termites carry slow-acting bait back to the colony | Takes time to work and is serviced yearly |
| Targeted soil treatment | Subterranean entry points | Non-repellent product placed in the soil where termites are entering | Used alongside bait at confirmed entry points |
| Annual program | Keeping coverage current | A yearly inspection that extends the warranty another year | Catches the next colony at the one-board stage |
Still working out what you found? The termite evidence guide goes sign by sign, including the look-alikes. Most drywood jobs in the San Gabriel Valley can be handled with a no-tent localized treatment, so fumigation is not our default; the spot treatment vs. tenting page lays out that decision, and the fumigation prep guide covers getting a house ready when a tent is the right call. As a licensed operator holding both the general (Branch 2) and termite (Branch 3) registrations, we give an honest assessment instead of a tent-first default; see what to expect during treatment or our termite control page.
How much damage do termites do?
The National Pest Management Association estimates termites cause about 6.8 billion dollars in property damage in the United States each year, and standard homeowners policies generally exclude it. The damage builds slowly: UC IPM puts drywood colonies at usually fewer than 1,000 termites that take years to mature, while mature subterranean colonies can reach hundreds of thousands. A colony caught at the one-board stage is a localized job; the same colony found years later is a repair bill. More numbers are in our California termite statistics.
How to prevent termites
- Keep wood at least 12 inches above the soil, as UC IPM recommends, and pull soil and mulch back from stucco, which can hide subterranean termites traveling behind it.
- Fix leaks, misdirected sprinklers and poor drainage; subterranean and dampwood termites follow moisture.
- Keep exterior wood painted and sealed and close attic vents with intact screens to keep drywood swarmers out of bare wood.
- Store firewood and lumber away from the house.
- Get an inspection every year or two, and sooner after a swarm; our termite prevention guide covers the rest.
Can you get rid of termites yourself?
Not reliably. The University of California does not recommend do-it-yourself treatment for drywood termites because colonies are hard to find and the products that work are not sold to the public. Store sprays kill the termites they touch and leave the colony. Our DIY termite treatment page explains what a homeowner can usefully do, starting with a photo of the evidence.
Sources
- UC IPM Pest Notes: Drywood Termites (University of California)
- UC IPM Pest Notes: Subterranean and Other Termites (University of California)
- National Pest Management Association: Five Termite Species All Homeowners Should Be Aware Of
- UC Riverside Entomology: Formosan Termites Confirmed in Two New Southern California Locations (2022)
Related Pests
Quick Answers
Quick Answers.
What are the first signs of termites?
The earliest signs are usually a pile of discarded wings after a swarm, small piles of pellets beneath wood (drywood termites), or mud tubes on the foundation (subterranean termites). Hollow-sounding or blistered wood often shows up later.
What's the difference between drywood and subterranean termites?
Drywood termites live entirely inside dry wood above ground and leave pellet piles; subterranean termites live in the soil and build mud tubes to reach wood. The two need different treatments, so correct identification matters.
How do I tell termite swarmers from flying ants?
Termite swarmers have straight antennae, a thick uniform waist, and two pairs of equal-length wings. Flying ants have elbowed antennae, a pinched waist, and front wings longer than the back pair.
How much damage can termites do?
Termites work silently for years, so the damage is often structural by the time it's found — weakened framing, floors and trim. Catching them early through regular inspection is far cheaper than repairing extensive damage later.
Do I always need to tent for termites?
Not always. A localized drywood infestation can often be handled with a targeted spot treatment, while whole-structure fumigation is reserved for widespread drywood activity. An honest inspection determines which is warranted — there's no tent-first default here.
How often should I have a termite inspection?
For most San Gabriel Valley homes, a professional inspection every one to two years is reasonable, and sooner if you spot swarmers, wings or pellets. Regular checks catch colonies while they're small and inexpensive to treat.
What do termites look like?
Workers are small, soft, pale and wingless, and you rarely see them. Swarmers are the ones people notice: dark or reddish-brown bodies with two pairs of equal-length wings, straight antennae and a thick waist. Drywood swarmers fly in daytime in summer and fall; subterranean swarmers fly after fall or spring rains.
What is the most common termite in California?
The University of California ranks the subterranean termite as California’s most important termite pest and the western drywood termite as the second. In the San Gabriel Valley we see both every week; drywood termites are especially common in older homes and exposed wood.
What attracts termites to a house?
Wood and moisture. Subterranean termites follow damp soil to wood touching or near the ground, so leaks, sprinklers against the foundation and stucco buried in soil all help them. Drywood swarmers land on bare, unsealed wood: eaves, fascia, patio covers and attic framing reached through open vents.
Do termites go away on their own?
No. A colony that has found food and moisture keeps feeding for years, and drywood colonies inside the wood never have a reason to leave. Damage only grows until the colony is treated. Here is the longer answer: do termites go away on their own?
Are Formosan termites in the San Gabriel Valley?
Not confirmed. The nearest confirmed finds are Highland Park and La Verne, both confirmed by UC Riverside in 2021 and 2022. An evening swarm of winged termites at a light between late May and early August is the sign worth reporting; see Formosan termites in California.
How long does termite treatment last?
Fumigation kills the drywood termites present that week and leaves no residual protection; localized treatment protects the treated wood; bait stations keep working while they are serviced. What keeps a house covered is the warranty and a yearly inspection. Details: how long termite treatment lasts.
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