Contra Costa County, CA Short-Term Rentals: Occupancy Limits (2026)

Unincorporated Contra Costa County does not have a dedicated STR ordinance establishing specific occupancy caps (e.g., 2 per bedroom), but the California Building Code and the county's adopted Housing Code place enforceable limits on how many people can lawfully occupy a dwelling. Under standard building code provisions, bedrooms must be at least 70 square feet for the first occupant and 50 additional square feet for each additional occupant. A common rule of thumb applied by insurers and platforms is 2 guests per bedroom plus 2 additional guests (e.g., a 3-bedroom home would accommodate 8). STR operators are also subject to noise, parking, and nuisance ordinances; exceeding reasonable occupancy can trigger code enforcement under Chapter 710-10 nuisance provisions or Chapter 716-8 noise rules. Septic system capacity is a practical limiter in rural unincorporated areas (Marsh Creek, Byron, Tassajara), where undersized systems cannot handle peak loads. Events, parties, and gatherings exceeding typical residential occupancy may require a temporary event permit and can be restricted by community plan policies.