Bozeman, MT Noise from Specific Sources: Generator Noise (2026)

Article 6 of Chapter 16 of the Bozeman Municipal Code never uses the word generator. The rules that reach a portable or standby generator are written around engines. Section 16.06.060.A.2 makes it unlawful, in areas zoned R-1, R-2, R-3, R-4, R-O, RMH, R-S or PLI, to discharge into open air the exhaust of any steam engine, stationary internal combustion engine, motorboat or motor vehicle except through a muffler or other device that effectively prevents loud or explosive noises. Section 16.06.060.A.4 goes further and bars operating any noise-creating blower, power fan, or internal combustion engine whose operation causes noise due to the explosion of operating gases or fluids, including snow removal devices, leaf blowers, chainsaws and lawnmowers, in a manner which may disturb the quiet, comfort or repose of any normally sensitive and reasonable person.

The hours that apply come from § 16.06.070.A.3, which authorizes operation of that equipment between 6:00 a.m. and 8:00 p.m. from October 1 through March 30 and between 6:00 a.m. and 10:00 p.m. from April 1 through September 30. The code prints no decibel limit for residential engine equipment. Decibel readings matter for construction operations, where noise from 8:00 p.m. to 7:00 a.m. must not exceed 60dB(A) at the property line of an immediately adjacent property (§ 16.06.090.C). A generator running on a construction site therefore faces both the engine rule and that overnight cap. The article also carves out emergency work, defined to include work by private or public utilities restoring utility service and work to protect persons or property from danger (§§ 16.06.040 and 16.06.080), so a generator running to restore power after an outage falls inside the exemption while a convenience generator does not. Outside the residential zones, the citywide rule in § 16.06.050.A.6 still bars any excessive or unusually loud noise in the City of Bozeman.