St. Louis County, MO Noise Ordinances: Vehicle Noise (2026)

078, part of the county's Petty Offenses Code chapter on disturbing the peace, singles out all-terrain vehicles rather than vehicle noise generally. ' The section defines 'residential property' broadly, as 'property which is zoned to permit single or multiple family housing,' so the 100-foot buffer runs from any lot zoned for housing, not just from an occupied house. It also defines 'all-terrain vehicle' as 'any motorized vehicle with three (3) wheels or four (4) wheels designed for use off of paved roads, but not including lawn care vehicles,' which pulls typical farm and recreational ATVs into the rule while carving out riding mowers and similar equipment.

Critically, the ordinance defines 'operate' as driving the machine 'a distance of more than one hundred (100) feet,' so a brief start-up or a few feet of movement in a driveway doesn't trigger a violation; sustained riding does. 073's general loud-noise rule, which asks whether sound is 'plainly audible' 50 feet away, this section doesn't measure decibels or audibility at all. It is a location-and-distance rule: an ATV that never comes within 100 feet of a residentially zoned lot and stays off paved roads and sidewalks is not covered, no matter how loud its engine is.

This section sits in the same Petty Offenses chapter as the county's general public-disturbance and barking-dog nuisance provisions, and it applies only in unincorporated St. Louis County.