National City, CA Noise from Specific Sources: Car Alarm Limits (2026)

The car alarm rule sits in Title 12, the city's noise code, in Chapter 12.10, Prohibited Acts. Section 12.10.240, Emergency signaling devices, has three subsections. Subsection A makes it unlawful to intentionally sound or permit the sounding outdoors of any fire, burglar or civil defense alarm, siren, whistle or similar stationary emergency signaling device except for emergency purposes. Subsection B governs testing of stationary emergency signaling devices, allowed only after seven a.m. and before seven p.m. and not to exceed sixty seconds per test. Subsection C is the vehicle rule: sounding or permitting the sounding of any exterior security or fire alarm or any motor vehicle security alarm for more than fifteen minutes is prohibited. The words permitting the sounding put the duty on whoever lets the alarm keep running, not only on the person who set it off.

Two cross-references shape how the rule works. Section 12.12.060 exempts activities covered by section 12.10.240 from the exterior noise limits of section 12.06.020, so a car alarm is judged by the fifteen minute time cap rather than a decibel level. And section 10.45.200 excludes alarm systems affixed to automobiles, boats, boat trailers, recreational vehicles and aircraft from Chapter 10.45, so the alarm user permit and false alarm penalties for building alarms do not apply to a car alarm.

Section 12.18.060 assigns nuisance noise to the chief of police or designate. The enforcing officer first issues an order requiring abatement, which can be written or verbal, and nuisance noise disturbances can be ordered abated immediately. If the source has a volume control device, the violator is allowed to adjust it until the volume complies. Failure to comply within the time specified can then be enforced criminally or civilly, or both. Section 12.18.100 adds that a device, instrument or vehicle causing sound levels exceeding the limits in Title 12 is declared a public nuisance subject to abatement by restraining order or injunction.