San Diego County, CA Accessory Structures: Tiny Homes (2026)
Tiny home rules in San Diego County, CA, covering tiny houses on wheels (THOWs), park model RVs, and tiny home on foundation builds, determine where they are legal and how they get permitted.
Key Facts
- Governing code
- County Residential Code Appendix BB
- Effective date
- April 3, 2026
- Enforcing agency
- Dept. of Planning & Development Services
- Scope
- Tiny houses as single dwelling units
- Area covered
- Unincorporated County only
Summary
Unincorporated San Diego County adopted Appendix BB of the California Residential Code as part of its County Residential Code, applying tiny-house building standards to tiny houses used as single dwelling units, effective April 3, 2026.
SEC. 92.2.RAPPBB. APPENDIX BB. Appendix BB of the California Residential Code is adopted in its entirety as part of the County Residential Code. APPENDIX BB TINY HOUSES RAPPBB 101.1 Scope. This appendix shall be applicable to tiny houses used as single dwelling units. Tiny houses shall comply with this code except as otherwise stated in this appendix.
Official source re-checked September 7, 2026: no newer edition of the code had been published (publisher’s edition: 2026 S-141: Administrative: Current through Ord. No. 11007 (N.S.), effective 7-10-26 | Regulatory: Current through Ord. No. 11008 (N.S.), effective 7-24-26).
Full Breakdown
The Board of Supervisors adopted Appendix BB of the California Residential Code in full as part of the County Residential Code at Section 92.2.RAPPBB, effective for unincorporated San Diego County since April 3, 2026 under Ordinance No. 10982. Appendix BB's scope section, RAPPBB 101.1, applies these standards specifically to tiny houses used as single dwelling units, which must otherwise comply with the standard Residential Code except where Appendix BB states otherwise. The County Department of Planning and Development Services, acting as building official, administers and enforces the County Residential Code, including permitting for any tiny house built under this appendix.
Violations & Fines
Building or occupying a tiny house without required permits, or in violation of adopted code provisions, is unlawful under Section 91.1.114.1 and treated as a public nuisance the building official can abate.
Frequently Asked Questions
Does this apply inside the City of San Diego?
What standards must a tiny house meet?
Sources & Official References
Other rules in San Diego County
California rules heatmap·Compare San Diego County to another location·View the California accessory structures overview
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