Colusa County, CA Noise Ordinances: Aircraft Noise (2026)

Chapter 13 of the Colusa County Code (Ord. No. 730) contains no section addressing aircraft, aviation, or airport noise; its noise limits apply to ground-based sources measured at the property plane. Aircraft noise is instead governed by federal and state law because local governments cannot independently regulate flight operations or aircraft noise standards. At the state level, California Code of Regulations, Title 21, Section 5012 establishes the standard for the acceptable level of aircraft noise for people living near airports as a community noise equivalent level (CNEL) of 65 decibels; airports designated as 'noise problem airports' cannot operate with a noise impact area exceeding that 65 dB CNEL standard without a variance. These standards are adopted by the California Department of Transportation (Caltrans) Division of Aeronautics under Public Utilities Code Section 21669, and Public Utilities Code Section 21669.4 makes it the function of the county in which an airport is situated to enforce the department's noise regulations. Because there is no county noise ordinance covering aircraft, residents of unincorporated Colusa County with aircraft-noise concerns generally direct them to the airport proprietor, Caltrans Aeronautics, or the Federal Aviation Administration rather than to the county noise code.