Aliso Viejo, CA Noise Ordinances: Decibel Limits (2026)

Section 8.12.050 of the Aliso Viejo Municipal Code sets exterior noise standards by land use and time. Residential property at a density of less than 10 DU/acre is held to 50 dB(A) from 7:00 a.m. to 10:00 p.m. and 45 dB(A) from 10:00 p.m. to 7:00 a.m. Residential property at 10 DU/acre or more is held to 55 dB(A) in the daytime period and 50 dB(A) at night. Nonresidential property is held to 65 dB(A) from 7:00 a.m. to 10:00 p.m. and 60 dB(A) from 10:00 p.m. to 7:00 a.m. for commercial uses, and 70 dB(A) for 24 hours per day for manufacturing and industrial uses. When the noise consists entirely of impact noise, simple tone noise, speech, music or any combination, each level is reduced by five dB(A). If a noise affects both residential and nonresidential property, the standard is the arithmetic mean of the two applicable standards.

Subsection (C) makes it unlawful to create or allow noise on controlled property that, measured on another parcel, exceeds the standard for a cumulative period of more than 30 minutes in any hour; the standard plus five dB(A) for more than 15 minutes; plus 10 dB(A) for more than five minutes; plus 15 dB(A) for more than one minute; or plus 20 dB(A) for any period. If ambient noise already exceeds a standard with the source off, the ambient level becomes the standard.

Interior limits under section 8.12.060 are 55 dB(A) from 7:00 a.m. to 10:00 p.m. and 45 dB(A) from 10:00 p.m. to 7:00 a.m. in residential dwellings, with a shorter cumulative window of more than five minutes in any hour. Section 8.12.040 requires a sound level meter, with exterior readings at any point on the affected property and interior readings at least four feet from the nearest wall, ceiling or floor with windows closed. Section 8.12.080 applies the residential limits at schools, hospitals and churches in use where signs are posted in three locations within one-tenth of a mile.