Termite Fumigation: How It Works, How Long It Takes, and When You Can Come Home

On this page

1. How long does termite fumigation take?
2. What termite fumigation kills, and what it does not
3. Before the tent goes up: the notice you sign
4. What happens during termite fumigation, day by day
5. When can you go back in after fumigation?
6. Does termite fumigation leave a residue?
7. What to do after termite fumigation
8. Is termite fumigation worth it? The trade-offs
9. Sources
10. Quick answers

How long does termite fumigation take?

Two to three nights out of the house for most homes. The tent goes up and the gas goes in on day one, the exposure period runs through the night and often the next day, then the house is aerated and the air is measured. The posted clearance usually comes on the third day, and the fumigator sets the exact schedule for your house, not the calendar. Here is the whole sequence.

What termite fumigation kills, and what it does not

Fumigation is a whole-structure treatment. The University of California defines that as treating every infestation in the house at once, including the ones no inspection could find, which is its real advantage over localized treatment: when drywood termites are in several places, or hidden behind drywall and stucco, the gas reaches them all. Sulfuryl fluoride kills drywood termites within several days, and a monitored fumigation has the highest success rate.

What it cannot do is reach a subterranean colony, which lives in the soil outside the tent. A tent does nothing to it. And because the gas leaves no residue, fumigation does not protect the house from the next swarm. If your activity is limited and accessible, you may not need a tent at all; our spot treatment vs. tenting page walks through that decision.

Before the tent goes up: the notice you sign

In California, the fumigation company must give you the state Occupant Fumigation Notice and Pesticide Disclosure form before the job and keep your signed copy on file; the rules for it were updated in 2025. The notice tells you the fumigant, the warning agent and what you are required to do. Read it. Then work through our fumigation prep checklist: the gas shutoff, two to three nights of lodging, bagging food and medicine, opening doors and cabinets, moving plants.

What happens during termite fumigation, day by day

Day one: the tent

The crew drapes tarps over the whole structure, clips the seams and weights the edges to the ground so the house holds gas. Pilot lights are off (the utility shut the gas earlier). Before the fumigant goes in, the crew releases chloropicrin, a tear-gas-like warning agent: sulfuryl fluoride is colorless and odorless, so the warning agent is what makes anyone still inside leave. Then the fumigant is introduced, the doors are locked, and warning signs go up on the structure.

The exposure period

The dose and the hold time are calculated for your house: its volume, the temperature, how well it seals. In a monitored fumigation, gas-monitoring lines run inside the structure and the fumigator checks that the concentration actually reached and held the target; the University of California notes that unmonitored fumigations can fall short of the needed concentration and fail. Ask whether yours is monitored.

Aeration

When the exposure period is complete, the house is aerated. Some crews vent through a stack with the tarps still on first; then the tarps come off, doors and windows are opened, and fans push the remaining gas out into the air.

When can you go back in after fumigation?

This is the part that is not negotiable. Before anyone re-enters, the licensed fumigator measures the air throughout the house with a detector. The National Pesticide Information Center notes that applicators monitor to make sure sulfuryl fluoride does not exceed the EPA limit of 1 part per million, and that occupants are not allowed back in until those checks are complete. When the readings are below the limit, the fumigator removes the warning signs and posts the re-entry notice. That posted clearance, not the number of days on the calendar, is what tells you the house is ready.

In practice that is usually the third day. If the readings are not there yet, it takes longer, and a crew that rushes it is a crew to avoid.

Does termite fumigation leave a residue?

• No residue. Sulfuryl fluoride is a gas; it disperses during aeration and leaves nothing on surfaces, so there is nothing to wash down. Food and medicine are bagged beforehand as a precaution, not because anything is left afterward.
• No lasting protection. The University of California is explicit that fumigants have no residual effect. The drywood termites present that week are gone; the next swarm can start a new colony. Protection going forward is a written warranty plus periodic inspections.
• The termites stay in the wood. Dead termites and their pellets remain inside the galleries. A few pellets can shake loose for a while afterward, which is why the pellet test (clean up, re-check in a few days for a fresh pile) is how activity is judged later, not a single pile.
• A greenhouse gas. The University of California notes sulfuryl fluoride was recently labeled a greenhouse gas. It is one more reason we recommend a tent only when the infestation calls for it.

What to do after termite fumigation

1. Keep the paperwork. The notice, the posted clearance and the written warranty. Our warranty guide explains what to look for in that document.
2. Restore gas service through your utility; the fumigator does not do that part.
3. Put food and medicine back. Anything factory-sealed in metal or glass that stayed is fine as it was.
4. Air the house if you like. It is cleared, and there is no residue; some people still prefer a day of open windows.
5. Plan the follow-up. Fumigation handles this week’s termites. An annual inspection is how next year’s get caught at the one-rafter stage. Here is who needs a yearly visit and who doesn’t.
6. Watch exposed wood. Drywood swarmers fly on warm late-summer and fall days and start new colonies in eaves, fascia and patio covers. Our flying termites guide covers when a few swarmers matter.

Is termite fumigation worth it? The trade-offs

Fumigation is effective, and it is also the most disruptive termite treatment: days out of the house, pets and plants relocated, a gas shutoff, and the possibility of roof damage from tarps dragged across tiles or crews walking on them, which the University of California lists as a real consideration. Sulfuryl fluoride is a toxic gas, and the whole clearance process exists because of it. That is why we inspect first and say which treatment the evidence supports. When the activity is limited and reachable, localized treatment handles it in one visit with you at home. When it is widespread or hidden, fumigation is the honest answer, and we will say so.

Sources

• UC IPM Pest Notes: Drywood Termites (University of California)
• National Pesticide Information Center: Structural Fumigation
• California Code of Regulations, Title 16 § 1970.4 (Occupant Fumigation Notice and Pesticide Disclosure)
• California Structural Pest Control Board: fumigation notice advisory (2025 amendments)