How Often Should You Clean a Dryer Vent? Washington's Fire Safety Guidance

What the Washington State Patrol recommends

The Washington State Patrol's dryer fire safety tips start from one point: the leading cause of home clothes dryer fires is the failure to clean them. Its recommendations cover three layers — the lint filter, the vent pipe, and the dryer itself:

• Lint filter: clean it before and after each load, and scrub it with a nylon brush at least every six months.
• Vent pipe: clean lint out every three months.
• The dryer: have it cleaned regularly by a professional, especially if drying takes longer than normal, and don't overload it.
• Gas dryers: have a professional inspect the gas line and connection every year.
• Habits: turn the dryer off when you leave home or go to bed.

Source: Washington State Patrol, State Fire Marshal's Office — Clothes Dryer Fire Safety (Nov. 17, 2022)

Why lint in the vent matters

The Consumer Product Safety Commission explains that lint can build up in the dryer or exhaust duct, block the flow of air, cause excessive heat, and result in a fire in some dryers. Nationally, the U.S. Fire Administration reports that failure to clean was the leading factor contributing to the ignition of home clothes dryer fires from 2018 to 2020.

Regular cleaning reduces that risk factor. It can't rule out every cause of a dryer fire, which is why the other habits on the list — like not running the dryer while you're away — still matter.

Sources: U.S. Consumer Product Safety Commission — Overheated Clothes Dryers Can Cause Fires (Publication 5022); U.S. Fire Administration — Appliance and Electrical Fire Safety

Signs your vent needs attention sooner

A three-month interval is a guideline, and lint can build up faster in some homes. Watch for these signs between cleanings:

• Clothes are still damp at the end of a typical cycle, or drying takes longer than normal (CPSC).
• Exhaust air isn't escaping from the outside vent while the dryer runs (CPSC).
• The outdoor vent covering doesn't open when the dryer is operating (USFA).
• The venting behind the dryer is damaged, crushed, or restricted (USFA).

Sources: U.S. Consumer Product Safety Commission — Overheated Clothes Dryers Can Cause Fires (Publication 5022); U.S. Fire Administration — Clothes Dryer Fire Safety (flyer)

The duct behind the dryer

Washington State Patrol's guidance calls for rigid or flexible metal venting material to sustain proper airflow. CPSC goes further on plastic and foil accordion-type duct: it traps lint more easily and is more likely to kink or crush, so CPSC recommends replacing it with rigid or corrugated semi-rigid metal duct.

Replacing duct is installation work. A vent cleaning clears lint from the run you have; if the run itself is the problem, that's worth knowing before you book repeat cleanings.

Sources: Washington State Patrol, State Fire Marshal's Office — Clothes Dryer Fire Safety (Nov. 17, 2022); U.S. Consumer Product Safety Commission — Overheated Clothes Dryers Can Cause Fires (Publication 5022)

Gas dryers: the vent and the gas line are separate jobs

The yearly gas dryer inspection Washington State Patrol recommends is about the gas line and connection — work for a qualified gas appliance professional. Dryer vent cleaning deals with the exhaust duct. If you have a gas dryer, plan for both, each on its own schedule.

Source: Washington State Patrol, State Fire Marshal's Office — Clothes Dryer Fire Safety (Nov. 17, 2022)