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

Policy NE-1c: Control non-transportation related noise from new projects. The total noise level resulting from new sources shall not exceed the standards in Table NE-2 as measured at the exterior property line of any adjacent noise sensitive land use. Limit exceptions to the following: (1) If the ambient noise level exceeds the standard in Table NE-2, adjust the standard to equal the ambient level, up to a maximum of 5 dBA above the standard, provided that no measurable increase (i.e. +/- 1.5 dBA) shall be allowed (2) Reduce the applicable standards in Table NE-2 by five dBA for simple tone noises, noises consisting primarily of speech or music, or for recurring impulsive noises, such as pile drivers and dog barking at kennels (3) Reduce the applicable standards in Table NE-2 by 5 decibels if the proposed use exceeds the ambient level by 10 or more decibels (4) For short term noise sources which are permitted to operate no more than six days per year, such as concerts or race events, the allowable noise exposures shown in Table NE2 may be increased by 5 dB. These events shall be subject to a noise management plan including provisions for maximum noise level limits, noise monitoring, complaint response and allowable hours of operation. The plan shall address potential cumulative noise impacts from all events in the area. --- Table NE-2 Maximum Allowable Exterior Noise Exposures for Nontransportation Noise Sources (Hourly Noise Metric, dBA; Daytime 7 a.m. to 10 p.m. / Nighttime 10 p.m. to 7 a.m.): L50 (30 minutes in any hour): 50 / 45; L25 (15 minutes in any hour): 55 / 50; L08 (4 minutes 48 seconds in any hour): 60 / 55; L02 (72 seconds in any hour): 65 / 60.