Subterranean Termites After Rain in Orange County
Termite swarmers after the rain?
Book a free licensed inspection with Halo Home Services.
Southern California's first cold, non-tropical storm of the rainy season moved through Orange County on October 21 and 22. The National Weather Service San Diego office's preliminary three-day totals showed about 0.76 inch at John Wayne Airport, 0.65 inch in Costa Mesa, 0.43 inch in Huntington Beach, and 1.10 inches in Anaheim Hills. If you live in Irvine, Fullerton, Garden Grove, or Mission Viejo and noticed a cloud of small, dark, winged insects on a warm, sunny afternoon after that rain, you may have seen subterranean termites swarming.
That is a reason to look closer, not to panic. According to the University of California Statewide IPM Program (UC IPM), western subterranean termites swarm on clear days after a soaking fall or spring rain, and a swarm in your yard does not necessarily mean your house is infested. Here is what the science says to check, and when to bring in a licensed inspector.
What subterranean termites are
UC IPM calls subterranean termites in the genus Reticulitermes the most destructive termites found in California. They live from the coastal dunes to the mountains, which puts every Orange County neighborhood in their range.
They nest in the soil, sometimes many feet down, not inside your walls.
They need moisture, so they stay connected to the soil and reach wood through earthen shelter tubes, often called mud tubes.
Mature colonies can hold hundreds of thousands of termites, and UC IPM notes a 2,400-square-foot home could have several colonies foraging around it.
Swarmers are dark brown to brownish-black with brownish-gray wings. Workers and soldiers are pale and wingless and stay out of sight.
Why fall rain matters in Orange County
Subterranean termites depend on damp soil. UC IPM reports that their best foraging conditions are warm temperatures and high soil moisture, and that those conditions are usually present under and around buildings.
In California these termites can forage year-round. UC IPM describes foraging as moderate in fall and spring and minimal from November to February.
A soaking rain followed by a warm, clear day is the classic trigger for a swarm.
Irrigated planters, sprinklers that hit the house, and stucco that runs down to the soil all keep the ground next to your foundation moist. UC IPM warns that stucco reaching the ground can let termites travel unseen between the stucco and the foundation.
Slab homes and older homes with crawlspaces are both at risk. The entry points just look different.
Signs of subterranean termites in your home
UC IPM lists the clues licensed inspectors look for:
Swarmers or piles of shed wings near windows and doors, especially on a sunny day after rain.
Mud tubes running up a foundation, stem wall, garage wall, pipe, or drywall. These are the most common sign of an infestation.
Wood that looks darkened or blistered, with a thin surface that is easy to puncture with a screwdriver.
Hollow galleries that follow the grain of the wood, sometimes with light-brown excrement inside.
Live, pale workers inside a broken tube or damaged wood. That is a sure sign of an active infestation.
Termite or flying ant? Termite swarmers have straight antennae, a thick waist, and two pairs of wings that are the same size. Winged ants have elbowed antennae and a pinched waist. If you find small, six-sided pellets instead of mud, that points to drywood termites, which need a different treatment plan.
Subterranean termite checklist for Orange County homeowners
Walk your foundation on a dry afternoon and look for mud tubes along slab edges, stem walls, garage walls, and pipes.
Photograph any tubes before you disturb them, so your inspector can see exactly where they came from.
Save a few swarmers or wings in a sealed plastic bag and note where and when you found them.
Pull soil, mulch, and planters back from stucco and wood. UC IPM recommends keeping structural wood at least 12 inches above the soil; check local building codes for the exact distance.
Fix plumbing leaks, clogged downspouts, and sprinklers that spray the house, and drain standing water.
Remove wood piles, buried scrap wood, old stumps, and untreated fence posts near the house.
Keep crawlspace vents clear so the area under the house stays dry.
DIY vs pro: what homeowners can and can't do
UC IPM is direct about this: homeowners are unlikely to control subterranean termites on their own. There are no reliable over-the-counter termite control products in California, and all effective products are for professional use only.
Methods used for drywood termites, such as fumigation and heat, do not work on subterranean termites, because the colony lives in the soil out of reach.
Licensed professionals use soil treatments with non-repellent active ingredients, such as fipronil, applied by label directions so termites cannot detect and avoid them.
Bait systems are another professional option. UC IPM notes they are slow-acting and can take months, so they need regular monitoring.
Your part is the prevention work above: dry soil, no wood-to-soil contact, and good records of what you see.
Schedule Your Free Termite Inspection
Saw swarmers or mud tubes after the rain? The first step is always a free licensed inspection, so you know which termite you have and exactly where it is active before any treatment is discussed.
How Halo Home Services helps with subterranean termites
Halo Home Services serves Orange County homeowners from Huntington Beach and helps families across Southern California. The core of what we do is the inspection. Our licensed inspectors identify which termite you have, where it is active, and which conditions are inviting it, and we document the findings on the state inspection report.
From there we explain the options from Halo's licensed practice, such as targeted soil treatment, monitoring and bait systems, and fixes for moisture and wood-to-soil contact, so the plan fits what was actually found. If the inspection turns up drywood termites instead, you may not have to tent: Halo's ADVANCE non-tenting drywood treatment is an option when a home qualifies.
If you have seen swarmers, wings, or mud tubes this fall, the first step is a free licensed inspection with Halo Home Services. Call 888-377-4256 (888-377-HALO), email Info@halohomeservices.com, or visit us at 16531 Bolsa Chica St #310, Huntington Beach, CA 92649.
Trusted sources
This article summarizes publicly available guidance for homeowners. For primary detail, see UC IPM Pest Notes: Subterranean and Other Termites (https://ipm.ucanr.edu/PMG/PESTNOTES/pn7415.html); the National Weather Service San Diego preliminary precipitation summary of October 24, 2026 (https://forecast.weather.gov/product.php?issuedby=SGX&product=RRM&site=sgx); LAist's October 20, 2026 report on the first cold storm of the rainy season (https://laist.com/news/climate-environment/southern-california-weather-october-rain); Halo Home Services' termite page (https://www.halohomeservices.com/termites); and the California Structural Pest Control Board (https://www.pestboard.ca.gov). Western subterranean termite swarmers photo by Ken-ichi Ueda via iNaturalist, licensed CC BY 4.0 via Wikimedia Commons. Always confirm any pest control firm is properly licensed before treatment.
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