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

Unlike many noise codes that rely only on time limits, Merced County's Chapter 10.60 includes numeric decibel standards. Section 10.60.030 establishes that, measured at the receiving real property line, the allowable noise level shall not exceed 65 dBA Ldn or 75 dBA Lmax on residential property, and shall not exceed 70 dBA Ldn or 80 dBA Lmax on nonresidential property. The County General Plan's Noise chapter confirms this, stating the County Code 'sets 65 dB Ldn and 75 dB Lmax standards for residential property, with standards applicable to nonresidential properties 5 dB higher.' The same section adds a relative test: a noise can be a violation when it exceeds the background sound level by at least 10 dBA during daytime hours (7:00 a.m. to 10:00 p.m.) and by at least 5 dBA during nighttime hours (10:00 p.m. to 7:00 a.m.). Ldn is the day-night average sound level, which applies a 10 dB penalty to nighttime noise, while Lmax is the maximum single-event level. Yard equipment has its own ceiling of 85 dBA (Section 10.60.030), and agricultural operations are exempt (Section 10.60.050). Measurements are typically taken by the Sheriff or Code Enforcement at the affected property line.