How Much Does Fumigation Cost in California? What Drives the Price

Cubic Volume, Not Square Footage

A fumigant fills a space, so the fumigator is buying volume rather than floor area. That distinction matters because two houses with the same listing square footage can hold very different amounts of air. A single-story ranch with an eight-foot ceiling and a shallow roof pitch is a small box. A two-story house with a steep gable, an open stair, and a vaulted great room holds far more, and the attic volume above the ceiling counts too, because the tent goes over the roof rather than around the top floor. The fumigator measures the structure and computes the volume rather than reading it off a floor plan, and that measurement is the first line of any honest estimate.

How Far the Infestation Has Spread, and Into What Wood

The fumigator sets a dosage rather than picking a package. The calculation combines the target pest, the outdoor and structural temperature, the exposure period, and the density of the wood the gas has to penetrate, because old-growth Douglas fir and redwood framing in a pre-1960 coastal house absorbs differently from modern kiln-dried lumber. Drywood termites deep in dense framing take a different dose than bed bugs in furnishings. A wider infestation does not simply mean more of the same work; it can change the dose, the exposure time, and the number of nights you are out of the house. This is why the inspection has to come before the number.

What the Tent Crew Has to Seal Around

Tenting is rigging work, and the property decides how hard it is. The same size house can be a straightforward morning or a full day of problem-solving depending on what sits on the roof and around the walls.

• Roof shape and covering — Steep pitches, multiple gables, and clay or slate tile all slow the crew and raise the risk of breakage, which is why tile roofs get their own conversation before the job.
• Rooftop equipment — Solar arrays, satellite mounts, swamp coolers, and antennas each have to be worked around or temporarily addressed.
• Lot lines and access — A house set close to the fence on both sides, or one with a steep driveway or a narrow gate, limits where the crew can stage tarps and run sandbags.
• Attached structures — Garages, carports, additions, and covered patios either come under the tent or get sealed off from it, and that decision changes the volume.
• Trees and landscaping — Overhanging limbs may need trimming, and plantings against the wall often need protection or clearance before tarps come down over them.
• Shared walls — A duplex, townhouse, or condo means neighbor coordination, and in most cases the adjoining unit has to be part of the plan rather than an afterthought.

County Permitting and Notice

California treats structural fumigation as its own licensed activity, separate from ordinary pest treatment, and the paperwork is part of the job rather than an extra. A licensed fumigator files a notice of intent with the county agricultural commissioner before the tent goes up, posts the required warning signage, installs secondary locks on the access points so nobody can walk into a charged structure, and issues a signed re-entry authorization only after a clearance reading. Monterey, Santa Cruz, San Benito, and Santa Clara counties each run their own agricultural commissioner office, and local notice practice, scheduling, and inspection follow-up differ enough between them to affect how a job is planned. Ask which county desk the notice goes to and who files it.

What Belongs in the Written Estimate

A complete written estimate names each of these, so you can compare one document against another line by line instead of comparing two bottom-line figures that were built differently.

• The inspection findings — What was found, where, and which species, rather than a bare recommendation to fumigate.
• The fumigant by name — Sulfuryl fluoride, sold as Vikane, is the standard for drywood termites. The estimate should say which product and on what dosage basis.
• Measured volume — The cubic footage the dosage was calculated against.
• Tenting and sealing — Who tarps the structure, how attached areas are handled, and what happens to landscaping and rooftop equipment.
• Clearance testing and re-entry — Confirmation that a clearance reading with a detection device, not a clock, decides when you go back in, and that a signed re-entry authorization is issued.
• Bags and preparation materials — Whether the sealed bags for food and medication are supplied.
• Notice and locks — Whether the county notice filing, signage, and secondary locks are part of the scope.
• Exclusions in plain language — What the estimate does not cover, written down rather than explained on the phone.

The Parts Homeowners Forget to Plan For

Several real costs of a fumigation never appear on a pest control estimate because the fumigator is not the one charging them, and they surprise people who budgeted only for the tent.

• Somewhere to stay — Everyone and every pet leaves the structure for the full exposure and aeration period, so lodging is on you and it depends on how many people and animals are in the household.
• Preparation time — Food, drinks, medication, and anything with a natural membrane such as fresh produce goes into sealed bags or leaves the house, and a full kitchen and bathroom take real time to work through.
• Structural repair — Fumigation ends the infestation; it does not replace a hollowed sill plate or a damaged rafter tail. Repairs are separate work and separately quoted.
• Roof and landscape touch-ups — Tile breakage and crushed plantings are uncommon but not unheard of, and the estimate should say who is responsible if either happens.

Fumigation or Local Treatment

Tenting is the right call when activity shows up in several disconnected places at once, when previous local treatments have not held, or when a real estate transaction needs the whole structure cleared rather than a list of treated spots. Local treatment, meaning orange oil, borates, or direct injection into a gallery, fits an infestation that inspection shows is confined to a few accessible members, and it does not require you to leave. The honest way to decide is not to guess which is cheaper. Ask for both approaches written into the same estimate for your property, with the inspection findings each one is based on, and compare them as documents.

Reading Two Estimates That Disagree

When two licensed operators look at the same house and hand you different documents, the difference usually traces to something specific rather than to one of them being unreasonable. Ask each of them the same five questions and the gap generally explains itself.

• Which fumigant, and at what dosage basis? A shorter exposure period or a lower concentration is a different job, not a discount.
• Is clearance testing part of the scope, or billed on its own?
• Was the volume measured at the property, or estimated from the curb?
• What is the license number, and what is covered if a tile breaks or a plant is crushed?
• What exactly is excluded, and is that list written into the estimate?