Contra Costa County, CA Short-Term Rentals: Noise Rules (2026)

Contra Costa County added Chapter 88-32 (Short-Term Rentals) to the Ordinance Code through Ordinance No. 2020-12 to regulate dwellings rented for thirty consecutive days or less in unincorporated areas. Among the operating standards, Chapter 88-32 prohibits excessive noise inconsistent with residential use and prohibits excessive traffic inconsistent with residential use. The county relies on a reasonableness standard rather than a numerical decibel threshold or a county-set quiet-hours window. Chapter 88-32 also caps total persons gathering at any STR at 20 and bars special events such as weddings, conferences, and commercial events, which materially limits the kind of large gatherings that typically trigger noise complaints. Operators must hold a Contra Costa County business license under Chapter 64-14 before renting and must designate a local responsible party who can respond to complaints. Chapter 88-32 only applies in the unincorporated county; cities within Contra Costa (Walnut Creek, Concord, Richmond, Antioch, Pittsburg, San Ramon, Danville, Lafayette, Orinda, Pleasant Hill, Martinez, Brentwood, El Cerrito, Hercules, Pinole, San Pablo, Oakley, Clayton, Moraga, Discovery Bay sphere) set their own STR or noise rules and many incorporated cities do publish numeric quiet hours and decibel limits. State-law fallbacks remain available throughout the county: California Penal Code Section 415 (disturbing the peace) and the disorderly-conduct provisions in Penal Code Section 647 give the Contra Costa County Sheriff a tool against loud parties even where the local rule is qualitative. STR registrations issued under Chapter 88-32 may be revoked or denied for repeated operating-standard violations.