Mono County, CA Noise Ordinances: Vehicle Noise (2026)

Mono County Code Chapter 10.16 does not establish its own decibel standard for cars and trucks on public roads. On-highway motor-vehicle noise is controlled by the California Vehicle Code, which preempts most local roadway-noise rules. Vehicle Code Section 27150 requires that every motor vehicle with an internal-combustion engine be equipped with an adequate muffler in constant operation and properly maintained to prevent excessive or unusual noise, and prohibits any cutout, bypass or similar device. Section 27151 makes it unlawful to modify an exhaust system to amplify or increase noise beyond what Section 27150 allows; for passenger vehicles under 6,000 pounds, an exhaust producing 95 dBA or less under the applicable SAE test is deemed compliant. The Mono County code does touch vehicles in two ways: Section 10.16.070(B)(12) requires that any motor, machinery, pump or generator be sufficiently enclosed or muffled so as not to create a noise disturbance, and Section 10.16.070(B)(10)(c) prohibits a motor-vehicle burglar alarm that is not terminated within five minutes of activation. Off-road vehicle and idling complaints in the unincorporated Eastern Sierra are typically handled under the general noise-disturbance standard or by the Sheriff under state law.