Contra Costa County, CA Noise Ordinances: Amplified Music & Outdoor Sound (2026)

The county has no general noise ordinance, so the Temporary Events Ordinance, Chapter 82-44, adopted by Ord. 2005-25 and amended by Ord. 2010-11 and Ord. 2024-07 (March 5, 2024), is the only place amplified music is regulated, and it turns entirely on head count. Section 82-44.206 defines an "event" as an organized outdoor assemblage that "exceeds seventy-five persons at a venue in a residential zoning district or at a venue in an agricultural zoning district or at a residence in any other zoning district; or exceeds one hundred fifty persons at any other venue or location," counting caterers, security and staff. Seventy-five or fewer at a home is "not an 'event' for purposes of this chapter", exactly the gap DCD's June 14, 2024 memo describes: parties "attended by 74 people or less in residential areas" are not subject to the ordinance's limits.

Cross the threshold and two rules apply to every event, permitted or not (§ 82-44.406(c)): the event may not exceed the noise levels in § 82-44.410, and "amplified sound by any device is prohibited after 8:00 p.m. Sundays through Thursdays and after 10:00 p.m. Fridays, Saturdays, and holidays." A permit cannot extend those hours (§ 82-44.410(b)(2)). The noise table, measured with a sound level meter at the exterior of a dwelling on another residential property, allows 60 dBA for 30 minutes in any hour, 65 dBA for 15 minutes, 70 dBA for 5 minutes and 75 dBA for 1 minute between 9 a.m. and 8 p.m., never exceeding 80 dBA; from 8 p.m. to 10 p.m. each figure drops 5 dBA, with a 75 dBA ceiling. Amplified sound "is prohibited in a residential district unless allowed as a condition of a temporary event permit" (§ 82-44.410(a)(12)).

A temporary event permit is applied for through DCD at least 45 days ahead (§ 82-44.408(c)) with a $500 application fee plus a $30 notification fee, and neighbors within 300 feet are mailed the permit conditions. A home in a residential district skips the permit for up to three events a year of 125 people or fewer, 200 on lots of 40,000 square feet or more, provided it meets the § 82-44.410(b)(1) sound levels, provides restrooms, gives DCD and every occupant within 200 feet ten days' written notice, and holds no commercial event (§ 82-44.408(h)); weddings, birthdays and graduations at a private residence are exempt up to four times in twelve months (§ 82-44.404(d)). Commercial events are barred from residential districts outright (§ 82-44.406(b)), and a venue in an agricultural district needs a land use permit capped at six events a year under 40 acres or 26 at 40 acres and up, with the same 8 p.m./10 p.m. amplified-sound cutoff (§ 82-44.416(f)).

Enforcement is shared: § 82-44.418 authorizes the Director of Conservation and Development and the Sheriff, allows "law enforcement and code enforcement officials" to monitor an event, and preserves every deputy's power under Penal Code § 415, the disturbing-the-peace statute. Below the event threshold, § 415 is the only lever, call the Sheriff's non-emergency line, (925) 646-2441. Car stereos are state law: Vehicle Code § 27007 bars a sound system audible 50 or more feet from the vehicle on a highway.