Olympia, WA Noise from Specific Sources: Car Alarm Limits (2026)

The City of Olympia, in Thurston County, Washington, handles repeated vehicle horn and siren noise through its disorderly conduct ordinance, Olympia Municipal Code § 9.16.020. Subsection D makes it disorderly conduct, when done knowingly and without lawful authority, to cause a public noise disturbance or to be in possession and control of property on which a public noise disturbance occurs. The code then lists sounds that are determined to be public noise disturbances, and item 1 is 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.

The text names horns and sirens attached to a motor vehicle. It does not use the words car alarm, and it sets no decibel number, no time of day and no count of cycles. The test is the printed one: frequent, repetitive or continuous sounding. The one-off chirp of a vehicle lock is not frequent, repetitive or continuous, while a horn or siren that keeps sounding is.

The possession-and-control language matters for vehicle owners. The offense reaches a person who causes the disturbance and also a person in possession and control of the property on which it occurs, so the owner of the vehicle or the premises where it sits is within the wording.

The list is not exclusive. The code closes with a proviso that the foregoing enumeration of acts and noises shall not be construed as excluding other acts and noises which offend the public peace.

The motor vehicle noise standards in OMC chapter 8.32 are a separate regime. They set muffler and tire-noise rules and sound levels in dBA measured at fifty feet, and they are enforced by the noise control officer, who is the chief of police for the city. They do not govern a sounding horn or siren, which falls under § 9.16.020(D)(1).