Porterville, CA Noise Ordinances: Decibel Limits (2026)

Porterville Municipal Code section 18-90.4 sets exterior noise level standards measured at the nearest residence, school, hospital, church or public library property line: an hourly Leq of 50 dBA and a maximum sound level (LMAX) of 70 dBA between 7:00 a.m. and 10:00 p.m., falling to an hourly Leq of 45 dBA and an LMAX of 65 dBA between 10:00 p.m. and 7:00 a.m. Section 18-90.5 sets a residential interior standard measured inside a neighboring dwelling unit: an LMAX of 55 dBA daytime and 45 dBA nighttime, on the same clock.

Both sections reduce every standard by 5 dB for pure tone noise or noise consisting mainly of speech or music, and both let the applicable standard float up to match the ambient noise level where the pre-existing ambient level already exceeds it. Section 18-90.3 lists the factors used to decide whether a sound is an unlawful nuisance, including volume, intensity, whether it is usual or unusual, its proximity to sleeping areas, and the zoning and density of the surrounding area, and treats a sound level more than 5 dB over the ambient level, measured at the property line or inside an adjoining unit for shared-wall buildings, as prima facie evidence of an unlawful noise. Measurements use an ANSI-standard sound level meter on the A-weighted, slow-response scale, calibrated immediately before use.