Termites

7 Early Signs of Termite Damage in California Homes

Termites cause billions in damage nationwide every year, and California's housing stock is prime territory. Here is what to look for before the damage gets structural.

Why California homes are at high risk

California's long dry summers and mild winters give termites a remarkably long active season. Subterranean termites nest in the soil and travel into homes through foundation gaps and slab cracks, while drywood termites fly straight into attics, eaves, and wall voids and need no contact with the ground at all. Both are common across the state's coastal and inland metros, with major swarm flights in spring and again on warm fall evenings.

1. Mud tubes on the foundation

Subterranean termites build pencil-width tunnels of soil and saliva up foundation walls, across slab edges, and along plumbing penetrations. These mud tubes protect them from dry air as they travel between soil and wood. If you snap one open and see pale, soft-bodied insects, the colony is active right now.

2. Discarded wings on windowsills

After a swarm, reproductive termites shed their wings. Piles of small, uniform, translucent wings on windowsills, in spider webs, or near exterior lights are a strong sign a colony swarmed nearby — possibly inside your walls.

3. Hollow-sounding or blistered wood

Termites eat wood from the inside out, leaving a thin shell. Tap baseboards, door frames, and window trim with a screwdriver handle: a papery or hollow sound is a warning. Paint that bubbles or blisters with no water source nearby can also signal tunneling just beneath the surface.

4. Frass (drywood termite droppings)

Drywood termites are the dominant species in much of California, and they push their droppings out of small kick-out holes. Frass looks like fine sawdust or ground pepper and accumulates in small cone-shaped piles below infested wood — commonly on windowsills, under eaves, and inside closets.

5. Sticking doors and windows

As termites tunnel through frames, the moisture they introduce warps the wood. A door or window that suddenly binds in its frame — without a seasonal swing or settling event to explain it — deserves a closer look.

6. Sagging floors or ceilings

Advanced infestations weaken structural members. Soft spots underfoot, dipping ceiling lines, or new cracks where walls meet ceilings can indicate damage that has moved well beyond cosmetic.

7. Clicking sounds in the walls

Soldier termites bang their heads against tunnel walls to signal danger. In a quiet room, a faint, dry clicking inside a wall is occasionally audible — an eerie but useful early warning.

What to do if you spot these signs

Do not disturb the evidence. Spraying a mud tube or a kick-out hole with store-bought insecticide kills a few workers and pushes the colony to reroute, making professional treatment harder. Note the location, take photos, and have a licensed professional inspect. Treatment options — liquid soil barriers, bait systems, localized spot treatment, or whole-structure fumigation for drywood colonies — depend entirely on the species and the extent of activity, which is exactly what an inspection determines.

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