Issaquah, WA Noise Ordinances: Vehicle Noise (2026)

Three items of IMC 9.22.010, Public disturbance noises – Restriction, speak to vehicles. The lead sentence makes it unlawful for any person to cause, or for any person in possession of property to allow to originate from the property, sound that is a public disturbance noise.

Subsection A covers the frequent, repetitive or continuous sounding of any horn or siren attached to a motor vehicle, except as a warning of danger or as specifically permitted or required by law. A single warning honk is outside the rule; repeated sounding for other reasons is inside it.

Subsection B covers frequent, repetitive or continuous sounds in connection with the starting, operation, repair, rebuilding or testing of any motor vehicle, motorcycle, off-highway vehicle or internal combustion engine within a residential district, so as to unreasonably disturb or interfere with the peace, comfort and repose of owners or possessors of real property. The residential district limit means a mechanic's bay in a commercial zone is not the target; a driveway engine rebuild is.

Subsection E sets the only numeric measure: sound from any motor vehicle audio sound system, such as tape players, radios and compact disc players, operated at volumes so as to be audible greater than 50 feet from the vehicle itself. The test is distance, not decibels, and it applies wherever the vehicle is.

Compression brakes are covered by a separate section. IMC 10.44.030 provides that no person shall use motor vehicle brakes which are in any way activated or operated by the compression of the engine, and it gives an affirmative defense where the brakes were applied in an emergency and were necessary for the protection of persons or property. Motorized foot scooters are tied back to IMC 9.22.010 by IMC 10.45's noise restriction subsection, which says their operation is subject to the public disturbance noises section.