Fullerton, CA Noise Ordinances: Decibel Limits (2026)

Orange County's Noise Control ordinance is built around measured A-weighted decibel limits. The whole County is designated 'Noise Zone 1' (Section 4-6-4). The exterior residential standard in Section 4-6-5 is 55 dB(A) from 7:00 a.m. to 10:00 p.m. and 50 dB(A) from 10:00 p.m. to 7:00 a.m.; the interior standard in Section 4-6-6 is 55 dB(A) by day and 45 dB(A) at night. Each limit is reduced by 5 dB(A) when the noise is entirely impact, simple-tone, speech, or music. Crucially, the limits are tied to duration: under Section 4-6-5(b) the exterior standard may not be exceeded for more than 30 cumulative minutes in any hour, and may be exceeded by 5 dB(A) for no more than 15 minutes, by 10 dB(A) for no more than 5 minutes, by 15 dB(A) for no more than 1 minute, and never by 20 dB(A) for any period of time. Interior limits in Section 4-6-6(b) tighten this to 5 minutes at the standard, 1 minute at +5 dB(A), and never +10 dB(A). Measurements use an ANSI-standard Type 1 or Type 2 sound level meter (Sections 4-6-2 and 4-6-3), taken at any point on the affected property or, for interior readings, at least 4 feet from the nearest wall, ceiling, or floor (Section 4-6-10).