Years — often three to eight, sometimes longer. Here's why termites stay hidden so long, what finally gives them away, and what that delay costs.
The question comes up almost every time we find a significant infestation: "How long has this been going on?" It's usually asked with a little dread, because the honest answer is often years. A colony can live and feed inside a home for a long time before anything visible gives it away — and that gap between infestation and discovery is exactly what makes termites so costly.
Why Termites Stay Hidden So Long
Termites are built to go unnoticed. Drywood termites live entirely sealed inside the wood they eat — no soil contact, no open trails, nothing to see from the surface until the colony is established enough to start pushing out frass or releasing swarmers. Subterranean termites travel inside mud tubes and eat wood from the inside out, often leaving a thin intact surface layer that looks completely normal.
A colony also starts small and grows slowly. In its first years, a young colony is tiny and produces almost no visible evidence. It can take several years just to reach the size where it makes frass in noticeable amounts or sends out its first swarm. For drywood termites in particular, the commonly cited range before obvious signs appear is roughly three to eight years — and in low-traffic areas like attics, it can be longer.
What Finally Gives Them Away
Termites are usually discovered in one of a handful of ways, and most of them happen by accident:
- A swarm. The colony matures and releases winged reproductives, and suddenly there are dark insects or piles of discarded wings on windowsills. This is the most common "aha" moment.
- Frass appears. A small pile of pellets shows up on a sill or floor and keeps coming back after cleanup.
- Something breaks. A baseboard gives under a vacuum, a doorframe flexes, a bit of trim crumbles.
- A sale triggers an inspection. A WDO/escrow inspection during a home sale finds activity the owner never knew about.
- A remodel opens a wall. Renovation exposes galleries that were hidden behind finished surfaces.
The through-line is that people rarely go looking — the termites announce themselves, usually years in.
What the Delay Costs
The problem with a multi-year head start is that termite damage compounds. A colony caught early, when it's small and localized, is often a straightforward, less expensive treatment. The same colony found five years later may have spread to multiple areas or into structural members, turning a simple treatment into a larger job with actual repair work attached. Nothing about termite damage gets cheaper by waiting — the cost curve only goes one direction.
That's the entire argument for not relying on visible signs to tell you when you have a problem. By the time the signs show up, the colony has already had its multi-year run.
How to Close the Gap
You can't make termites announce themselves sooner, but you can go looking on a schedule instead of waiting for an accident. An annual inspection is designed to catch activity in that hidden window — before frass, before a swarm, before something breaks — which is why it's the single most effective thing a Southern California homeowner can do. We make the case in detail in why annual termite inspections save you thousands, and the 5 warning signs of a termite infestation covers what to watch for between inspections.
If it's been more than a year since your home was last inspected — or if it's never been inspected — that hidden window is exactly what a free inspection is built to check. It's free, there's no obligation, and it's how you find out whether the answer to "how long has this been going on?" is "not long" instead of "years."