Boulder County, CO Noise Ordinances: Decibel Limits (2026)

050 of the county's 1992 noise ordinance sets a table of dB(A) ceilings by vehicle type and road speed limit: motorcycles built before 1/1/1973 are capped at 82 dB(A) on roads posted 35 mph or less and 86 dB(A) above that; motorcycles built after that date get 80/84 dB(A); vehicles with a manufacturer's gross vehicle weight rating of 10,000 lbs or more (and anything they tow) top out at 86/88 dB(A); every other vehicle is held to 80/84 dB(A). Off a public road or highway, on private or non-road public property, every vehicle is limited to a flat 78 dB(A) regardless of type.

040 fixes how the county measures compliance: 50 feet from the center of the travel lane for roadway sound, 50 feet from the vehicle for off-road sound, using an ANSI-standard A-weighted sound level meter, with readings only taken when wind is under 5 mph (25 mph with a wind screen). 050(E) layers on a separate rule for periodic, impulsive or shrill noise: it is unlawful whenever it hits a level just 5 dB(A) below the applicable table limit, since short spikes read as more disruptive than steady noise at the same average level.

030 independently declares that operating any vehicle, machine or device above these levels is prohibited. 060 include emergency vehicles responding to calls, agricultural equipment on a farm or ranch, and activities under a county special use permit that addresses noise.