San Bernardino County, CA Noise Ordinances: Decibel Limits (2026)

San Bernardino County Code Title 8 Division 3 structures its noise limits around the receiving land use rather than the noise source. Typical A-weighted (dBA) limits measured at the property line include: (1) Residential zones (R-1, R-2, R-3 and rural RL): 55 dBA from 7 AM-10 PM, 45 dBA from 10 PM-7 AM; (2) Commercial zones (C, CN, CG): 65 dBA day, 60 dBA night; (3) Industrial zones (IC, IR): 70 dBA day and night. The ordinance applies correction factors: simple-tone noise gets a -5 dB penalty, impulsive noise (hammering, gunshots, metal stamping) gets a -5 dB penalty, and repetitive impulsive noise can get a combined -10 dB adjustment. California Environmental Quality Act (CEQA) reviews of new development use the Community Noise Equivalent Level (CNEL) or day-night average sound level (Ldn) to analyze compatibility over a 24-hour period. These metrics add 5 dB to evening hours (7-10 PM) and 10 dB to nighttime hours (10 PM-7 AM) to reflect community annoyance. The 65 dB CNEL contour is the standard threshold for residential compatibility near airports, highways (I-10, I-15, I-215, SR-210), and rail lines.