Mariposa County, CA Noise Ordinances: Industrial Noise (2026)

Mariposa County does not regulate industrial noise through a standing ordinance or a countywide decibel table. The General Plan Noise Element (Chapter 15) observes that environmental noise sources such as 'large local industrial plants; and other stationary noise sources do not occur in Mariposa County, and as such are not evaluated for noise exposure,' reflecting the county's rural, low-industry character. Where industrial or other non-residential noise does arise, it is managed through land-use review rather than a nuisance ordinance. General Plan Implementation Measure 15-2b(1) provides that 'where proposed non-residential land uses are likely to produce excessive noise levels at existing or planned noise-sensitive uses, an acoustical analysis shall be required as part of the project review process,' prepared by a qualified professional, including noise measurements, recommended mitigation, and post-project effectiveness assessment. Measure 15.1a(2) further directs that 'County development standards shall require means of controlling noise at its source as opposed to imposing mitigation.' These controls are administered by the Mariposa County Planning Department through zoning, conditional-use permits and review under the California Environmental Quality Act (CEQA). As a result, the operative noise limits for any given industrial or commercial site come from that site's permit conditions and acoustical study, not a general code section. Neighbors concerned about an industrial noise source should raise it with the Planning Department and review the facility's permit and environmental documents.