Contra Costa County, CA Rental Property Rules: Rental Registration (2026)

Unincorporated Contra Costa County has no general rental registration or rental licensing program applicable to most residential rental properties, unlike some cities within the County (such as Richmond and Concord, which have rent programs). Landlords of long-term residential rentals in unincorporated CCC are instead subject to California state law, including the Tenant Protection Act of 2019 (AB 1482) which caps annual rent increases at 5 percent plus CPI (not to exceed 10 percent) on most properties built 15+ years prior and imposes just-cause eviction standards. Properties exempt from AB 1482 include single-family homes not owned by a corporation (with proper notice), newer construction, and certain affordable housing. The California Civil Code sections on security deposits (Civil Code 1950.5), habitability (1941+), and source-of-income discrimination (under the California Fair Employment and Housing Act) apply. Short-term rentals (under 30 days) require transient occupancy tax (TOT) registration with the County Treasurer-Tax Collector and compliance with zoning. Mobile home parks are regulated under California Mobilehome Residency Law (MRL). The County Health Department may inspect rental housing in response to habitability complaints. Mobile home parks require permits from HCD for certain changes. A business license may be required if the landlord operates more than a threshold number of units.