National City, CA Noise from Specific Sources: HVAC & Mechanical Noise (2026)

National City Municipal Code § 12.10.320 contains no decibel figure of its own for cooling or ventilation equipment. It points to the sound levels in § 12.06.020, so the number that governs is the one for the property receiving the sound. The section heading reads Residential air conditioning or air handling equipment, but the operative sentence covers any air conditioning or air-handling equipment.

Table III of Chapter 12.06 lists the exterior limits in dB(A). All residential property with fewer than 9 dwelling units is held to 45 from 10 p.m. to 7 a.m. and 55 from 7 a.m. to 10 p.m. Multi-unit residential property of 9 dwelling units or more, and public space, is held to 50 at night and 60 by day. Commercial property is held to 60 and 65. Light industry east of I-5 is held to 70 in both periods, and heavy industry west of I-5 to 80 in both periods.

Under § 12.06.020(E)(3) the level is measured at the boundary of the property on which the sound is produced, or at any point within the boundary of the property affected. Section 12.06.020(D) reaches noise created on property a person owns, leases, occupies or otherwise controls. Section 12.06.040(C) lowers the Table III limits by five dB when the noise contains a steady, audible sound such as a whine, screech or hum, and § 12.06.040(D) makes the measured ambient level the standard when ambient already exceeds the table figure.

Section 12.18.060 gives the chief of police or designate enforcement of nuisance noise, including conditions under Chapter 12.10, while § 12.18.040 gives environmental noise to the planning director. Under § 12.18.090 the code enforcement officer measures with a sound level meter whenever practicable, with the microphone four to five feet above the ground and at least ten feet from the source if possible. Under § 12.06.020(E)(2), failure or inability to measure does not bar enforcement or abatement.