San Jacinto, CA Noise Ordinances: Vehicle Noise (2026)

San Jacinto Municipal Code § 8.40.150 has three sentences. First, the use of any motor vehicle in such a condition as to create excessive, impulsive or intrusive noises is prohibited. Second, the discharge into the open air of the exhaust of any internal combustion engine, stationary or mounted on wheels, motorboat or motor vehicle, including motorcycle, is prohibited when it creates excessive, unusual, impulsive or intrusive noise, and the code says this applies whether or not the exhaust is discharged through a muffler or other similar device. Third, motor vehicles must comply with the noise regulations of the California Vehicle Code. The section prints no decibel number, so the test is whether the noise is excessive, unusual, impulsive or intrusive.

The section does not name stereos or engine brakes. Vehicle sound systems fall under two other pieces of the chapter. Section 8.40.120 says electronic devices used in vehicles and heard only by occupants of the vehicle in which installed are not sound-amplifying equipment, so a stereo audible only inside the car is outside the amplified sound permit rules. A stereo that projects loud music outside the vehicle is covered by § 8.40.080, which bars loud, excessive, impulsive or intrusive noise from any mechanical or electrical sound-making or sound-amplifying device that disturbs the peace or annoys a reasonable person of normal sensitivities.

The mobile noise source table in § 8.40.040 sets 65 dB(A) exterior and 45 dB(A) interior for residential land uses, but it applies to development and infrastructure projects, not to an individual car. Public safety personnel and their equipment, whether stationary or mobile, are exempt under § 8.40.070(C). The San Jacinto police department receives and investigates complaints under § 8.40.190, and its peace officers issue warning notices and citations.