Downey Decibel Limits Rules (2026): What You Need to Know

Downey Municipal Code Chapter 6 (Unnecessary Noises) sets measurable, objective noise standards for the city. The primary enforcement threshold is any noise exceeding 100 dBA when measured at 25 or more feet from the source — this constitutes a prima facie violation without further analysis. A second standard applies when a complainant requests a measurement: if the measured level exceeds the prevailing ambient noise level by one or more A-weighted decibels (adjusted for daytime or nighttime conditions), the source is found in violation.

The ordinance restricts the use of power tools, heavy machinery, and similar equipment in residential zones (R-1, R-2, R-3) between 10 PM and 7 AM if such use disturbs the peace, comfort, or repose of neighboring inhabitants. Commercial and manufacturing zones located within 300 feet of any residential use are subject to the same nighttime equipment restrictions. Equipment such as air-conditioning, refrigeration, heating, pumping, and filtering systems installed prior to the effective date of the noise ordinance may exceed the ambient standard by no more than 8 dBA, and only for a period not exceeding five years from June 22, 1976.

The Downey Police Department handles general noise complaints, while the Code Enforcement Division manages property-related violations. Residents who request a follow-up noise measurement test when a prior test within the previous six months found no violation must deposit $100 with the City before the test is conducted.