Los Angeles County, CA Noise Ordinances: Decibel Limits (2026)
Key Facts
- Daytime limit
- 43 dBA L90 (8:00 am to 8:00 pm)
- Nighttime limit
- 38 dBA L90 (8:00 pm to 8:00 am)
- Measurement point
- Property line closest to nearest residential receptor
- Topanga Canyon subarea daytime limit
- 48 dBA L90
- Amplified outdoor sound
- Prohibited 8 pm to 8 am
Summary
The Santa Monica Mountains North Area Community Standards District caps daytime exterior noise at 43 dBA L90 (8 am–8 pm) and nighttime at 38 dBA L90 (8 pm–8 am), measured at the property line nearest the closest residential receptor.
L.Noise.1.The daytime exterior noise level shall not exceed 43 dBA at a L90 measurement in any hour from 8:00 a.m. until 8:00 p.m. The nighttime exterior noise level shall not exceed 38 dBA at a L90 measurement in any hour from 8:00 p.m. until 8:00 a.m. Noise levels are considered a nuisance when they exceed these ambient noise levels when measured from the property line closest to the nearest residential receptor.2.Outdoor amplified sound shall be prohibited between the hours of 8:00 p.m. and 8:00 a.m. within the North Area.3.Where a new land use is proposed to be located within 2,000 feet of a land use with a lower ambient noise standard, the new use shall not exceed the ambient noise limits of the more sensitive use.4.Due to the existing above-average ambient noise conditions in the Topanga Canyon area, the daytime exterior noise level shall not exceed 48 dBA at a L90 measurement in any hour from 8:00 a.m. until 8:00 p.m. for the Topanga Canyon subarea. Noise levels are considered a nuisance when they exceed this ambient noise level when measured from the property line closest to the nearest residential receptor.5.Building construction noise is exempt from the ambient noise limit set forth in this Section, but remains subject to Chapter 12.12 of County Code.
Full Breakdown
LA County Code § 22.336.070.L sets ambient noise limits for the Santa Monica Mountains North Area CSD in unincorporated LA County. Daytime exterior noise must not exceed 43 dBA at an L90 measurement in any hour from 8:00 a.m. to 8:00 p.m.; nighttime must not exceed 38 dBA from 8:00 p.m. to 8:00 a.m. Noise exceeding these thresholds is declared a nuisance when measured from the property line closest to the nearest residential receptor. A higher limit of 48 dBA L90 daytime applies to the Topanga Canyon subarea due to existing above-average ambient conditions. Outdoor amplified sound is banned between 8 pm and 8 am throughout the North Area. Building construction noise is exempt from these limits but remains subject to County Code Chapter 12.12. Where a new land use is proposed within 2,000 feet of a use with a lower ambient noise standard, the new use must comply with the more sensitive standard.
Violations & Fines
Exceeding 43 dBA daytime or 38 dBA nighttime (measured at the property line) is declared a nuisance. Outdoor amplified sound between 8 pm and 8 am is prohibited.
Frequently Asked Questions
When is noise considered a nuisance in the Santa Monica Mountains North Area?
Does construction noise follow these limits?
Is the Topanga Canyon area subject to different rules?
Sources & Official References
Other rules in Los Angeles County
California rules heatmap·Compare Los Angeles County to another location·View the California noise ordinances overview
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