Fond du Lac County, WI Noise from Specific Sources: Car Alarm Limits (2026)

Sec. 38-173(b)(1) of the county code, part of the general noise ordinance for unincorporated Fond du Lac County, targets three distinct acts involving vehicle horns and signal devices. First, it bars sounding any horn or signal device on an automobile, motorcycle, bus or other vehicle except as a genuine danger signal or while brakes are being applied. Second, it separately bars creating an unreasonable, loud or harsh sound by means of any signal device. Third, and most directly relevant to a car alarm that will not stop, it bars sounding a signal device for any unnecessary or unreasonable period of time.

The ordinance does not define a specific cutoff, such as a set number of minutes, after which an alarm becomes a violation; a deputy responding to a complaint applies the 'unnecessary or unreasonable period of time' language to the facts. Because this sits inside the same Sec. 38-173 that opens with a general ban on unreasonably loud or disturbing noise, an alarm that repeatedly triggers overnight in a rural subdivision outside any city or village limit can be cited even without a witnessed danger. Enforcement and penalties track the rest of the noise ordinance: a citation issued under § 1-9's Uniform Municipal Citation procedure and a forfeiture under § 1-8 upon conviction.