Does cleaning the lint trap not deal with it?

Only partly. The trap catches some of what comes off a load and the remainder enters the duct. In a long or bendy run, a good proportion of that settles rather than reaching the outside. Emptying the trap every load is worth doing and does not prevent duct accumulation.

How often should it be done?

It depends entirely on usage and on the duct run. A household doing several loads a day through a long run with multiple bends needs it far more often than a two-person household with a short straight run. Drying time is a better guide than any interval anyone can quote you.

What kind of ducting should I have?

Rigid metal with a smooth interior for the run through the house, which is what the California Mechanical Code requires. A listed flexible transition duct of up to 6 feet is allowed between the dryer and the wall, as long as it stays out in the open. Foil or plastic accordion ducting hidden inside a wall or ceiling is the kind to replace: the ridges catch lint, it crushes easily, and the plastic type can burn.

Can a dryer vent into a chimney?

No. The California Mechanical Code prohibits connecting a dryer duct to a chimney or gas vent. In older houses a duct is sometimes found running up a disused flue; if yours does, that is worth sorting out before anything else. Cleaning a dryer duct and cleaning a chimney are otherwise separate jobs.

The accessible portions and the exterior termination, reasonably. The difficulty with a long or concealed run is reaching the middle of it — kits sold for the purpose often clear the first few feet and leave the rest, which can give false reassurance. Verifying airflow at the termination afterwards is the check that actually tells you.

Depends on duct length and routing

Dryer Vent Cleaning in California

Clearing the lint that accumulates in the duct rather than the lint trap

Request an Estimate Describe the problem

Chimney & Fireplace

Sweeping, inspection and repair

Wood, Gas & Factory-Built

Different systems, different work

Inspection Is Separate

Not bundled into a cleaning

California Service Areas

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What Dryer Vent Cleaning Covers

The lint trap catches a portion of what comes off a load. The rest goes into the duct, and in a long or convoluted run a good deal of it settles there rather than reaching the outside. That accumulation restricts airflow, which makes the dryer work harder and run longer, and lint is readily combustible in a duct carrying heated air. It is a maintenance item that is almost never thought about until the dryer stops drying properly — which is itself the main symptom, and a reasonably reliable one.

This is a separate system from the chimney and it is worth saying so — the two are frequently bundled but they are unrelated ducting. For chimney work, chimney sweep and cleaning covers the flue side of things.

What is included

Restores airflow so the dryer completes a cycle in a normal time
Removes accumulated lint from the full duct run, not just the accessible end
Reduces the fire load in ducting that carries heated air
Clears the exterior termination and its flap, a common blockage point
Identifies crushed, disconnected or improperly routed ducting

How the work goes

Assess the run
Length, number of bends and material. A short straight run behaves completely differently from a long run with several elbows.
Disconnect and inspect
The connection at the appliance is a common failure point, and a disconnected duct venting into a wall cavity is a genuine problem worth finding.
Clear the duct
Mechanically, along the full run rather than as far as the equipment easily reaches.
Clear the termination
The exterior hood and its flap collect lint and are a common blockage point in their own right. Also where birds nest.
Verify airflow
The test is whether air is moving properly at the termination with the dryer running, not whether the duct looks clean at one end.

The Symptom Is Reliable

Unusually among maintenance items, this one announces itself clearly. If loads that used to dry in one cycle now need two, the duct is restricted. That is close to a direct measurement of airflow.

Other signs point the same way: the laundry room becoming noticeably hot and humid during a cycle, the exterior of the dryer running hot to the touch, or a faint burning smell. If you are seeing any of those and the lint trap is clean, the duct is where to look.

Duct Material Matters More Than People Think

Flexible foil or plastic accordion-style ducting is still found behind a great many dryers, and it is the worst option available. The ridged interior catches lint at every corrugation, it crushes easily when the dryer is pushed back, and the plastic type is combustible in a duct carrying heated air.

The California Mechanical Code asks for the duct itself to be rigid metal with a smooth interior, at least 4 inches across. The only flexible piece it allows is a listed transition duct between the dryer and the wall: no more than 6 feet long, and never hidden inside a wall, floor or ceiling. If accordion ducting runs out of sight through the structure, that section is worth replacing, and a cleaning visit is a good time to find out.

What California Code Says About Dryer Ducts

For a standard 4-inch duct, the 2025 California Mechanical Code (section 504.4.2.1) allows a combined run of 14 feet including two 90-degree bends, and takes 2 feet off for every bend beyond two. A longer run needs either a listed dryer-duct booster fan installed to its maker's instructions, or the dryer manufacturer's permission and the local building department's approval.

The same section sets the rest of the rules. The duct has to end outdoors with a back-draft damper, never in a crawl space, attic or wall cavity. There should be no screen over the outlet, because a screen catches lint, and no screws poking into the duct for the same reason. A dryer duct can never be connected to a chimney or gas vent.

Where the Duct Actually Goes

Worth confirming rather than assuming. A duct that has come adrift behind the appliance, or one that terminates in a crawl space, attic or wall cavity rather than outside, is discharging warm moist lint-laden air into the structure.

This is more common than it should be, particularly after an appliance has been moved or replaced. It causes moisture problems that get attributed to entirely different things, and it is the sort of fault that can persist for years unnoticed.

Dryer Vent Cleaning by city

Local pages covering how this service differs in each market. All service areas

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Dryer Vent Cleaning — common questions

The clearest sign is drying time. If loads that used to take one cycle now take two, the duct is restricted. Others are a laundry room that gets hot and humid during a cycle, a dryer cabinet that runs hot to the touch, or a faint burning smell. If the lint trap is clean and you are seeing these, the duct is the place to look.

Not sure whether dryer vent cleaning is what you need?

Tell us what the chimney or fireplace is actually doing and we will tell you which service applies — including when the answer is that you do not need one yet.

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