Chapel Hill, NC Noise from Specific Sources: Car Alarm Limits (2026)

Section 11-39.1(a)(11) of the Noise Control Code lists among its enumerated nuisance noises the 'sounding of a security alarm, for more than twenty (20) minutes after the owner or responsible party has been notified by law enforcement personnel,' a category that covers a car alarm left blaring after the Chapel Hill Police Department reaches the owner. Before that twenty-minute clock starts, an alarm going off is not automatically a violation; the provision is triggered only once law enforcement has made contact and the alarm keeps sounding past the twenty-minute mark.

The alarm nuisance sits within the same Article III framework that lets a person subject to any § 11-39.1 nuisance be given an oral order to cease or abate the noise under § 11-42(a), though such an order is not required before enforcement. General nuisance-noise complaints under § 11-42(b) normally require two complainants from two locations twenty minutes apart, but a persistent alarm that officers themselves have already timed and traced to a notified owner does not depend on neighbor complaints in the same way.

Officers measure the noise against the underlying decibel standards in § 11-39, 50 dBA daytime and 45 dBA nighttime at a residential boundary, when deciding whether the alarm itself also independently exceeds the property-line limits.