Isleton, CA Noise Ordinances: Decibel Limits (2026)

The core numeric standards for unincorporated Sacramento County are found in County Code Section 6.68.070 (Exterior Noise Standards). In residential zones, the maximum permissible exterior noise level is 55 dBA between 7 a.m. and 10 p.m. and 50 dBA between 10 p.m. and 7 a.m. It is unlawful to create noise that causes the level on an affected property to exceed the applicable standard in any one hour. The ordinance includes important adjustments. Each noise limit is reduced by 5 dBA for impulsive or simple-tone noises, or for noise consisting of speech or music, making those sources subject to stricter effective caps. Conversely, if the ambient (background) noise level already exceeds a given category's limit, the allowable limit is raised in 5 dBA increments to encompass the ambient level, so the standard adapts to noisy environments. Measurement methodology matters: the county selects a point at least one foot inside the property line of the affected residential property, with the microphone where feasible three to five feet above the ground and at least four feet from walls or other reflecting surfaces. These standards underpin the related noise rules for amplified music, industrial sources and mechanical equipment, and they are the figures EMD uses when investigating habitual or mechanical noise complaints with a sound level meter.