Quiet hours in Altadena, CA — also called the noise ordinance, nighttime noise rules, or residential quiet time — define the hours during which excessive noise is prohibited.
Altadena is unincorporated, so LA County Title 12 Chapter 12.08 (Noise Control) applies. Nighttime exterior limits run 10:00 p.m. to 7:00 a.m. with stricter dB caps; daytime runs 7:00 a.m. to 10:00 p.m.
Under LA County Code Section 12.08.390 and the Part 3 Community Noise Criteria tables, exterior noise in single-family residential areas may not exceed 45 dBA at night (10 p.m.–7 a.m.) and 50 dBA during the day. Multi-family residential daytime is 55 dBA, nighttime 50 dBA. Commercial zones are 60 dBA day / 55 dBA night, and industrial zones are 70 dBA at all times. Section 12.08.380 also forbids exceeding the ambient noise level by more than 5 dB on another property regardless of zone.
Per Section 12.08.560 and Chapter 1.25, violations are infractions or misdemeanors. Administrative citations typically run $100 (first offense), $200 (second within 12 months), and $500 (third), and each day of continuing violation is a separate offense.
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Side-by-side rule comparisons with other cities in Los Angeles County.
See how other cities in Los Angeles County handle quiet hours.
See how Altadena's quiet hours rules stack up against other locations.
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