Aliso Viejo, CA Noise from Specific Sources: HVAC & Mechanical Noise (2026)

Section 8.12.030 of the Aliso Viejo Municipal Code defines a fixed noise source as a stationary device that creates sound while fixed or motionless, and lists air conditioners alongside fans, compressors, pumps, generators, leaf blowers, public address systems and refrigeration equipment. Noise level means the A-weighted sound pressure level in decibels from a sound level meter at slow response, written dB(A). That puts a residential or commercial air conditioner, condenser or rooftop unit squarely inside the city noise chapter.

Section 8.12.040 says exterior noise is measured with a sound level meter at any point on the affected property, and interior noise inside the affected dwelling unit at a point at least four feet from the wall, ceiling or floor nearest the source with windows closed. Section 8.12.050 then sets the exterior standards: for residential property, 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. at a density of less than 10 DU/acre, and 55 and 50 dB(A) at 10 DU/acre or more. Commercial property is held to 65 dB(A) in the day and 60 dB(A) at night, and manufacturing or industrial property to 70 dB(A) around the clock. Speech, music, impact or simple tone noise is reduced by five dB(A), which matters for a unit with a humming tone. None of the exemptions in section 8.12.070 names air conditioning equipment.

Placement is governed by section 15.14.040(A)(7): air conditioning, ventilation and similar equipment can sit in rear and side yard setbacks, is not permitted in front yard setbacks, and existing equipment less than three feet from a property line can be replaced at the same setback if the setback does not decrease. Encroachments under that section must keep a minimum distance of three feet from all property lines in residential districts. Condominium owners also need homeowners association approval before adding new units in common area, though replacing existing units at the same location does not.