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

Santa Ana's noise standards under Chapter 18 of the Municipal Code use A-weighted decibel measurements (dBA) to set maximum allowable noise levels based on the zoning of the receiving property and the time of day. For residential zones, the exterior standard is 55 dBA during the day (7 AM to 10 PM) and 50 dBA at night (10 PM to 7 AM). Commercial and mixed-use zones carry higher thresholds of 65 dBA during the day and 60 dBA at night. Industrial zones are set at 70 dBA at all times. Measurements are taken at or near the property line of the affected property, not at the source.

The General Plan Noise Element provides additional guidance using the Community Noise Equivalent Level (CNEL) metric, which is a 24-hour weighted average that applies a 5 dB penalty for evening hours (7 PM to 10 PM) and a 10 dB penalty for nighttime hours (10 PM to 7 AM). The Noise Element establishes that new residential development should not be exposed to exterior levels exceeding 65 dBA CNEL and that interior habitable rooms must achieve 45 dBA CNEL or lower. These CNEL standards are primarily applied during the planning and environmental review process for new construction and land use changes, while the Chapter 18 instantaneous standards govern day-to-day enforcement.

Given Santa Ana's position as the densest city in Orange County and one of the densest in California, noise conflicts are common. The mix of single-family neighborhoods adjacent to commercial corridors, industrial areas, and major transportation infrastructure — including the I-5 and SR-55 freeways, John Wayne Airport flight paths, and the Metrolink/Amtrak rail corridor — creates a complex noise environment. Code Enforcement officers are equipped with calibrated sound level meters and will respond to measurement-based complaints. Residents should note the time, duration, and nature of noise when filing a complaint.