San Diego County has two termite problems, not one. Subterranean termites live in the soil and tunnel up into wood through mud tubes, while drywood termites live entirely inside dry wood above ground and leave behind pellet-like frass. Both are common here, they look and behave differently, and a licensed structural pest operator – not a general home inspector – does the actual wood-destroying organism (WDO) inspection and treatment.
Why San Diego gets both kinds
Most of the country worries mainly about subterranean termites. San Diego’s mild, dry coastal climate is also ideal for drywood termites, so local homeowners realistically face two separate species with two separate playbooks. The older bungalows in North Park and Kensington, the stucco-and-wood homes inland in San Marcos and Escondido, and the coastal properties in Encinitas and Carlsbad each have their own exposure depending on soil contact, moisture, and the age of the framing.
Knowing which type you may be dealing with matters because the inspection focus, the treatment, and the long-term prevention are completely different. Confusing the two leads people to spend money on the wrong fix.
Subterranean termites: the ones that come up from the ground
Subterranean termites nest in the soil and need contact with moisture to survive. They reach your framing by building mud tubes – pencil-width tunnels of soil and saliva that run up foundation walls, piers, and the stem wall. These tubes protect them from drying out as they travel between the ground and the wood they eat.
Signs to look for around a San Diego home:
- Mud tubes climbing the foundation, garage slab edges, or crawl space piers.
- Wood that sounds hollow when tapped, often with soil packed inside the galleries.
- Damage that follows the grain and tends to start low, near the soil line, sill plates, and any wood touching dirt.
- Swarmers (winged reproductives) and discarded wings near windows, usually after rain.
Subterranean colonies can be large and do structural damage faster than drywood, especially where there’s a moisture source – a leaking hose bib, poor drainage against the foundation, or an over-irrigated planter bed pressed up against stucco. In our area, earth-to-wood contact and chronic dampness are the two biggest invitations.
Drywood termites: the ones already living in the wood
Drywood termites don’t need soil contact or much moisture at all. A small swarm flies in, finds a crack or an unsealed wood surface – exposed fascia, eaves, attic framing, a wood fence, window trim – and burrows in to start a colony entirely inside the wood. That’s why they show up in second-story framing and attics, places subterranean termites rarely reach.
The signature sign is frass: tiny, dry, six-sided pellets the termites push out of small “kick-out” holes. Frass often looks like little piles of coarse pepper, sawdust, or coffee grounds collecting on windowsills, along baseboards, in the garage, or on the floor below infested framing. You may also see the pinholes themselves and faint blistering on the wood surface.
Quick way to keep them straight: subterranean = mud tubes from the ground; drywood = frass pellets falling from the wood. Drywood colonies grow more slowly, but because they can establish in many separate spots throughout a structure, a bad case can mean multiple infestations at once.
Where a home inspection fits – and where it stops
This is the important part, and it’s where a lot of buyers get confused. A general home inspection is a visual, non-invasive evaluation of the home’s major systems. During an inspection we routinely notice conditions associated with termites – visible mud tubes, frass, obvious wood damage, conducive conditions like earth-to-wood contact, leaks, and poor drainage – and we document and call them out.
What a general inspection is not is an official WDO inspection. We do not treat termites, we do not fumigate, and we do not issue the wood-destroying organisms report that lenders and escrow often require. In California, that work is performed by a licensed structural pest control operator – a separate, specialized license and report. When we see signs of activity, we tell you clearly and refer you to a licensed pest operator who can do the proper WDO inspection and recommend treatment. We refer; we don’t treat.
That division protects you. You get an independent set of eyes flagging the problem (us), and a licensed specialist diagnosing and pricing the fix (the pest operator) – without the conflict of interest that comes when the same company both finds and sells the treatment. To understand the broader boundaries of a standard inspection, see our guide on what a home inspection does not cover, and for the full WDO picture read our breakdown of termite and WDO inspections in San Diego.
What the licensed pest operator actually does
A structural pest operator performs a dedicated WDO inspection and produces a report that typically separates findings into active infestations, evidence of past activity, and conducive conditions. Treatment depends on the species and how widespread it is:
- Subterranean infestations are usually handled with soil-applied termiticide barriers or in-ground bait systems, plus correcting the moisture and wood-to-soil issues feeding them.
- Drywood infestations may be treated with localized methods (spot treatments, borate, heat) for limited cases, or whole-structure fumigation – “tenting” – when the colonies are widespread.
Which approach is right is the pest operator’s call, made under their license. Always get the WDO report and the treatment recommendation in writing, and feel free to get a second opinion before committing to fumigation.
Telling termites from look-alikes
Not every pile of dust or damaged board is termites. Carpenter ants tunnel through wood but leave a coarser, fibrous debris rather than neat pellets. Plain wood rot from chronic moisture – soft, crumbling, often discolored framing – can look like insect damage and frequently shows up in the same damp spots termites love, but it’s a moisture problem, not a bug. The two even travel together: a leak that rots a sill plate also makes that wood far more attractive to subterranean termites. A licensed pest operator distinguishes active insect activity from old damage and from simple decay, which is exactly why their report carries weight in a real estate transaction.
What San Diego homeowners can do
You can’t inspect your way out of a colony, but you can make your home far less appealing:
- Keep soil, mulch, and planters from touching stucco and wood siding.
- Fix leaks and improve drainage so water runs away from the foundation.
- Store firewood and lumber off the ground and away from the house.
- Seal exposed wood – eaves, fascia, trim – and screen attic and foundation vents.
- Watch windowsills and the garage floor for frass, and check the foundation for mud tubes a couple of times a year.
If you’re buying or selling in San Diego County and want a thorough, independent look at the home before you bring in a pest operator, reach out to The Real Estate Inspection Company at (619) 752-4399. We’ll document any termite signs we see, explain what they likely mean, and point you to the right licensed specialist for the WDO inspection and treatment.
