Westminster, CA Noise Ordinances: Vehicle Noise (2026)

The City of Westminster's Noise Control chapter (WMC 8.28) sets ambient property-line dB(A) limits but does not contain a separate vehicle-exhaust standard, and motor-vehicle noise on public roadways is largely preempted by the California Vehicle Code, which the state controls. Under California Vehicle Code Section 27150, every motor vehicle subject to registration must at all times be equipped with an adequate muffler in constant operation and properly maintained to prevent excessive or unusual noise, and no muffler or exhaust system may be equipped with a cutout, bypass, or similar device. Section 27151 makes it unlawful to modify a vehicle's exhaust system in a manner that amplifies or increases the noise emitted so the vehicle no longer complies with Section 27150 or exceeds the noise limits for its vehicle type, and it is likewise unlawful to operate such a modified vehicle. For exhaust systems on vehicles with a manufacturer's gross vehicle weight rating under 6,000 pounds (other than motorcycles), a sound level of 95 dBA or less under the applicable SAE test is treated as compliant. These state standards apply citywide and are typically enforced by the Westminster Police Department through the Vehicle Code. Stationary vehicle noise on private property - such as a parked car with a blaring stereo or an idling vehicle running equipment - can additionally be reached under WMC Chapter 8.28's general dB(A) limits and public-nuisance provisions. Off-road or stationary engine noise not covered by the Vehicle Code falls back on the city's noise standards.