Tent fumigation has no residual protection. Termidor lasts 10+ years. Orange oil has no residual. Here's exactly what to expect from each treatment type long-term.
Treatment vs Protection: A Critical Distinction
Before answering "how long does treatment last," it's important to separate two different things:
- Treatment — eliminating the current infestation
- Protection — preventing a new infestation from establishing
Most termite treatments do one but not both. Understanding this distinction is what determines whether you need annual inspections, follow-up treatments, or just a periodic check-in.
Tent Fumigation: Eliminates Current Infestation, Zero Residual
What it does: Fumigation with Vikane (sulfuryl fluoride) gas kills all drywood termite life stages — eggs, nymphs, soldiers, reproductives — throughout the entire structure during the fumigation period.
What it doesn't do: The gas dissipates entirely by the time the home is cleared for re-entry. Once the clearance test shows safe Vikane levels, there is no active chemical left anywhere in the home. A new drywood termite swarmer can enter through a roof vent the day after clearance.
Recommended follow-up: Annual inspection. Fumigation effectively resets the clock — but the clock starts running again immediately.
How long before re-infestation is possible: Immediately after clearance.
Termidor (Fipronil Soil Barrier): 10+ Years
What it does: Termidor creates a treated zone in the soil around the structure's foundation. Subterranean termites foraging through treated soil pick up the fipronil, carry it back to the colony, and transfer it to other colony members — collapsing the entire colony.
Why it lasts so long: Fipronil is highly stable in soil when applied correctly. It doesn't break down from rain or irrigation at normal rates. Studies and field experience consistently show 10+ year efficacy.
What it doesn't cover: Termidor is a subterranean termite treatment only. It has no effect on drywood termites living in above-ground wood.
Recommended follow-up: Annual inspection to confirm no new drywood activity and to verify the Termidor zone remains intact (especially important after major landscape disturbance near the foundation).
Orange Oil: No Residual
What it does: d-limonene (orange oil) injected directly into termite galleries kills termites on contact within the treated galleries. Effective for early-stage, localized, accessible drywood infestations where galleries can be physically reached.
What it doesn't do: Orange oil has no residual protection — it doesn't penetrate beyond the injected area and breaks down quickly. It doesn't protect against new swarmers entering from outside.
Critical limitation: Orange oil is a localized treatment. If there are untreated galleries elsewhere in the structure (which there often are, especially in attic framing), those colonies continue unaffected.
Recommended follow-up: Re-inspections at 30, 90, and 365 days to confirm no new or continued activity.
Heat Treatment: No Residual, Same-Day Return
What it does: Raises the interior temperature of the structure to 120–140°F — lethal to all termite life stages throughout the structure. Chemical-free. Same day as treatment, occupants can return once the structure cools.
What it doesn't do: Like fumigation, heat leaves no residual. The structure is clear on day one, but a new swarmer can enter on day two.
Recommended follow-up: Annual inspection. Identical follow-up protocol to fumigation.
Borate Treatment: Long-Lasting Wood Protection
What it does: Borate (disodium octaborate tetrahydrate) penetrates wood fibers and is toxic to termites and fungi on contact. Applied to accessible framing, it provides long-lasting protection.
Why it lasts: Borate doesn't evaporate or break down under normal conditions when protected from rain. Applied to interior framing before drywall installation, it can remain effective for decades.
Best use case: New construction or major renovation where bare framing is accessible. Applying borate before drywall is one of the best long-term investments a homeowner can make — $400–$900 for decades of protection.
Limitation: Borate must penetrate the wood surface. It can't be effectively applied to finished, painted, or stained wood.
Summary Table
| Treatment | Eliminates Current Infestation | Residual Protection | Longevity | Follow-up |
|---|---|---|---|---|
| Tent Fumigation | Yes | None | Zero residual | Annual inspection |
| Heat Treatment | Yes | None | Zero residual | Annual inspection |
| Orange Oil | Localized only | None | Zero residual | 30/90/365 day re-inspection |
| Termidor | Yes (subterranean) | Yes (subterranean) | 10+ years | Annual inspection |
| Borate | Prevention only | Yes (on treated wood) | Decades | Annual inspection |
What Annual Inspection Means in Practice
An annual inspection is a full re-inspection of the structure by a licensed inspector — attic, subarea, garage, all exterior, and accessible interior. It typically takes 45–90 minutes. The goal is catching any new activity before it becomes a significant infestation requiring expensive whole-structure treatment.
For most Southern California homeowners, annual inspection + rapid response to new activity is far more cost-effective than any "set and forget" treatment approach.
Related: Tent Fumigation · Termidor Treatment · Orange Oil Treatment