Lynnwood, WA Noise Ordinances: Vehicle Noise (2026)
Key Facts
- Muffler requirement
- LMC 10.12.300(B)(4)
- Stereo audibility rule
- Plainly audible at 50 feet
- Auto/light truck limit
- 72 dBA at 45 mph or less
- Stereo violation penalty
- Class 1 civil infraction
- Muffler violation penalty
- Misdemeanor, LMC 10.12.800
Summary
Lynnwood, Washington requires every motor vehicle exhaust to run through a working muffler and bans stereo or radio noise loud enough to be heard 50 feet from the vehicle, under LMC 10.12.300(B)(4) and (B)(9). Motor vehicles must also stay under separate decibel ceilings set in LMC 10.12.600's sound-level tables.
4. To discharge into the open air the exhaust of any steam engine, stationary internal combustion engine or motor vehicle, except through a muffler or other device which will effectively reduce loud or explosive noises therefrom; ... 9. The use, operation, or permitting to be used, played or operated any radio receiving set, musical instrument, phonograph, or other machine or device for the producing or reproducing of sound in such manner as to unreasonably disturb the peace, quiet and comfort of the neighboring inhabitants or at any time with louder volume than is necessary for convenient hearing for the person or persons who are in the room, vehicle or chamber in which such machine or device is operated and who are voluntary listeners thereto. The operation of any such set, instrument, phonograph, machine or device in such a manner as to be plainly audible at a distance of 50 feet from the building, structure or vehicle in which it is located shall be prima facie evidence of a violation of this section;
Official source re-checked September 8, 2026: no newer edition of the code had been published (publisher’s edition: current through Ordinance 3512, passed May 26, 2026).
Full Breakdown
Lynnwood's noise ordinance targets vehicle sound in two distinct ways. 300(B)(4) makes it unlawful to discharge a steam engine, stationary internal combustion engine, or motor vehicle's exhaust into the open air except through a muffler or other device that effectively reduces loud or explosive noise. 300(B)(9) separately bans operating a car stereo, radio or similar sound device so it unreasonably disturbs neighboring inhabitants, and it builds in an evidentiary shortcut: if the sound is plainly audible 50 feet from the vehicle, that is prima facie evidence of a violation, meaning no decibel meter is required to cite the driver.
600 sets numeric sound-level ceilings for in-use motor vehicles, measured 50 feet from the travel lane: 78 dBA for motorcycles and 72 dBA for automobiles and light trucks at 45 mph or less, rising at higher speeds, plus separate exhaust-system ceilings measured 20 inches from the tailpipe (95 dBA for pre-1986 automobiles). 37 RCW by trained law enforcement personnel who may require a vehicle be presented for sound-level testing. 600 violations remain misdemeanors.
Violations & Fines
A defective-muffler violation of LMC 10.12.300(B)(4) or an exhaust-level violation of LMC 10.12.600 is a misdemeanor under LMC 10.12.800. A car-stereo violation of LMC 10.12.300(B)(9) is instead a Class 1 civil infraction under RCW 7.80.120, and in-use vehicle sound-level violations are also enforced as traffic infractions under Chapter 46.37 RCW.
Frequently Asked Questions
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Sources & Official References
Other rules in Lynnwood
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