Union City, CA Noise from Specific Sources: Car Alarm Limits (2026)
Key Facts
- Governing section
- UCMC § 9.40.043(C)
- Applies to
- Horns and vehicle warning alarms
- Trigger for violation
- Sounded at rest, no imminent threat
- Complaint route
- Planning Department, § 9.40.070
Summary
Union City bars using a vehicle horn or car alarm when the vehicle is parked unless there is an actual, imminent threat to life, health, or property.
Vehicle horns, or other devices primarily intended to create a loud noise for warning purposes, shall not be used when the vehicle is at rest, or when a situation endangering life, health, or property is not imminent.
Official source re-checked September 7, 2026: no newer edition of the code had been published (publisher’s edition: rev 4940544; v16 updated 2026-06-23).
Full Breakdown
Under Union City Municipal Code § 9.40.043(C), vehicle horns and "other devices primarily intended to create a loud noise for warning purposes", which covers aftermarket and factory car alarms, cannot be sounded while the vehicle is at rest unless a real emergency is happening. A car alarm that just goes off from a bump, weather, or a false trigger with no genuine threat present violates this public-property noise provision, on top of the chapter's general noise-disturbance rules in Article IV.
Violations & Fines
Enforced as a noise disturbance under Union City Municipal Code Chapter 9.40; complaints are filed with the Planning Department per § 9.40.070.
Frequently Asked Questions
Can my car alarm go off if someone tries to break in?
Who do I complain to about a neighbor's blaring car alarm?
Sources & Official References
Other rules in Union City
California rules heatmap·Compare Union City to another location·View the California noise from specific sources overview
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Car Alarm Limits in Nearby Cities
How other cities in Alameda County handle car alarm limits.