Imperial County, CA Noise Ordinances: Decibel Limits (2026)

Unincorporated Imperial County uses objective decibel limits set out in Title 9, Division 7, Section 90702.00. It is unlawful to cause noise so that the applicable one-hour average sound level is exceeded at or beyond the boundary of the property producing the noise. The limits, measured using A-weighting and slow time-averaging, are: R-1 residential, 50 dB from 7 a.m. to 10 p.m. and 45 dB from 10 p.m. to 7 a.m.; R-2 residential, 55 dB day and 50 dB night; R-3, R-4 and all other residential, 55 dB day and 50 dB night; all commercial, 60 dB day and 55 dB night; manufacturing and all other industrial, including agricultural and extraction industry, 70 dB at any time; and general industrial, 75 dB at any time. Where two zoning districts meet, the limit is measured at the property line between them. Fixed-location public utility distribution or transmission facilities on or adjacent to a property line are measured at least six feet beyond the easement boundary. Several activities are exempt: permitted fireworks displays, helicopters at permitted heliports or helistops, standard agricultural field operations such as planting and harvesting (the County has a Right to Farm Ordinance), and governmental functions where reasonable noise mitigation is applied. The County also uses Community Noise Equivalent Level (CNEL), which adds 5 dB to evening (7-10 p.m.) and 10 dB to nighttime (10 p.m.-7 a.m.) sound levels for 24-hour planning measurements.