Prince George's County, MD Noise from Specific Sources: Car Alarm Limits (2026)

Section 19-122 of the County Code, part of Subtitle 19's Division 2 noise control chapter, sets the baseline: a person may not cause or permit noise that exceeds the maximum allowable dBA levels for the receiving property's land use category (65 dBA daytime and 55 dBA nighttime for residential receiving property under § 19-122(a)(1)), and separately may not cause or permit noise that creates a 'noise disturbance' under § 19-122(b), defined in § 19-121(11) as sound that is unpleasant, annoying, or unusual for the time and place it occurs regardless of the decibel reading.

Section 19-122(c) lists illustrative acts that violate the section 'if they exceed the noise level standards set in subsection (a) or create a noise disturbance,' and the first example is sounding a horn or other signaling device on a motor vehicle on private property. That covers a car alarm that keeps sounding in a driveway or parking lot. The ordinance exempts a horn or alarm used in a genuine emergency, or as a daytime warning signal that still complies with the applicable dBA limit. is far more likely to cross the line than the same alarm at noon.

The Department of Permitting, Inspections, and Enforcement (DPIE) and the Prince George's County Police Department both hold enforcement authority under § 19-121(5)-(7), and either can respond to a complaint about a vehicle alarm that will not stop. Sound is measured under § 19-126 using equipment meeting ANSI, ASTM, or EPA standards, generally taken at the receiving property line.