Trinity County, CA Noise Ordinances: Decibel Limits (2026)

There is no single 'decibel limits' chapter in the Trinity County Code; the operative numbers are spread across the zoning title and the General Plan. The clearest exterior figures are the General Plan noise-level standards the Code expressly adopts for land-use noise: Section 17.43.060 (Commercial Cannabis Cultivation) states cultivation 'shall not exceed the noise level standards as set forth in the county general plan: 55 A-weighted decibels (dBA) from seven a.m. to seven p.m. and 50 dBA from seven p.m. to seven a.m. measured at the property line.' These day/night exterior values function as the County's general benchmark. For industrial uses, Chapter 17.30 performance standards, Section 17.30.100(C), set a more technical limit: 'at the lot line the maximum sound pressure level radiated in each standard octave band by any use or facility ... shall not exceed' the values in Table I (for example 79 dB at 20-75 cycles per second, decreasing across higher octave bands to 39 dB at 4,800-9,600 cps), measured with a sound-level meter and octave-band analyzer on the flat or 'C' network. Table II adds corrections (e.g., +5 dB for daytime-only operation; lower limits for noise radiated between 10:00 p.m. and 7:00 a.m.). For home occupations, Section 17.30B.060 caps major home-occupation noise at 'fifty-five dBA as measured at the property line during allowable hours' and provides that noise 'shall not be noticeable or exceed thirty-two dBA as measured at the property line after allowable hours.' These standards apply countywide, but they are land-use and zoning standards rather than a universal residential quiet-hours decibel cap.