San Diego County deals with two very different termite problems, and homeowners often assume they're the same thing. They're not. Subterranean and drywood termites look different, live differently, and — most importantly — need different treatments. Confusing the two can mean paying for the wrong service, or worse, missing an infestation entirely.
Where They Live
Subterranean termites live in the soil and build colonies underground, traveling up into a structure through pencil-thin mud tubes that run along foundations, piers, and walls. They need consistent moisture and a connection back to the soil to survive, which is why you'll usually find mud tubes near the foundation, in crawl spaces, or along slab edges.
Drywood termites skip the soil entirely. A swarming pair lands on exposed or weathered wood — an eave, a fascia board, attic framing — and the colony lives entirely inside that piece of wood for its whole life. No mud tubes, no soil contact required. This is why drywood termites show up in dry attics and upper-floor framing where subterranean termites generally can't reach.
Signs of Subterranean Termites
Mud tubes on foundation walls or piers, wood that sounds hollow near ground level, and swarmers (winged reproductives) appearing near soil, mulch beds, or ground-floor windows — typically in spring after a rain.
Signs of Drywood Termites
Small hexagonal fecal pellets (frass) that look like coffee grounds or fine sawdust piled below infested wood, discarded wings near attic vents or upper windows, and hollow-sounding wood in areas with no soil contact, like roof eaves or door frames. We cover this in more detail in our drywood termite warning signs article.
Why the Distinction Changes Your Treatment
Subterranean termite colonies are connected to the soil and often span a much wider area than what's visible above ground, so treatment typically targets the soil and foundation perimeter — cutting the colony off from the structure. Because the infestation source is outside the structure, treatment usually doesn't require tenting.
Drywood termite colonies are self-contained inside the wood itself, with no soil connection to treat. Depending on how localized the infestation is, that means either a targeted spot treatment for isolated areas, or fumigation (tenting) when the infestation has spread through multiple structural members or is difficult to access directly.
The Bottom Line
The single biggest mistake homeowners make is treating a drywood problem like a subterranean one, or vice versa — it wastes money and leaves the actual colony intact. An inspection identifies which species you're dealing with and how far it's spread, so the treatment matches the actual problem instead of guessing.
Request a free termite inspection and we'll tell you exactly which type you're dealing with — and the most cost-effective way to deal with it.