Downey, CA Accessory Structures: Tiny Homes (2026)
Tiny home rules in Downey, 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 section
- Downey Municipal Code § 8993
- Appendix adopted
- Appendix BB, Tiny Houses
- Base code
- 2025 California Residential Code
- Adopted by
- Ordinance 26-1537, 1/27/2026
- Enforcing agency
- Building and Safety Division
- Max penalty
- $1,000 fine or 6 months jail
Summary
Downey lets residents build tiny houses under Appendix BB of the 2025 California Residential Code, adopted by reference as the "Downey Building Code" in Municipal Code Section 8993. A tiny house still needs a full building permit reviewed by the Building and Safety Division and must meet the appendix's reduced ceiling-height, egress, loft and stair standards rather than standard single-family dwelling requirements.
Except as provided herein, the 2025 Edition of the California Residential Code, (California Code of Regulations, Title 24, Part 2.5), based upon the 2024 International Residential Code, including Appendix BB (Tiny Houses), BF (Patio Covers), BG (Sound Transmission), and C1 (Swimming Pool Safety Act), is hereby adopted by reference as though fully set forth herein, and shall constitute and is hereby established as the "Downey Building Code." A copy of the 2025 Edition of the California Residential Code is on file in the Building and Safety Division and the office of the City Clerk for use and examination by the public.
Full Breakdown
" Appendix BB sets the construction standards a structure must meet to be permitted and inspected as a tiny house rather than a standard dwelling or accessory structure, covering reduced minimum ceiling heights, loft sleeping areas, alternate egress and ladder or alternating-tread stair provisions the base Residential Code does not otherwise allow. Because Downey adopted the appendix without a local exception carving it out, a tiny house built to Appendix BB standards is treated exactly as the 2025 CRC provides, and plans are reviewed by the Building and Safety Division against that text.
The same Section 8993 also folds in seismic and structural amendments the city layered onto the 2025 Residential Code elsewhere in the chapter, including Section 8994's requirement that a licensed architect or engineer stamp construction documents for wood-frame dwellings over two stories in higher seismic design categories, and Section 8997's anchorage rules for mechanical, electrical and plumbing equipment; a tiny house project must clear these citywide amendments in addition to Appendix BB itself. A copy of the adopted 2025 California Residential Code, with Appendix BB, is on file for public inspection in the Building and Safety Division and the City Clerk's office.
Violations & Fines
A tiny house built or occupied without the building permit Section 8993 requires, or that departs from Appendix BB's ceiling-height, egress or stair standards without an approved alternative, is treated as a Code violation under Section 1200: a misdemeanor punishable by up to a $1,000 fine or six months in jail, or an infraction with fines from $100 up to $500 for repeat violations, and the city can red-tag or require removal of unpermitted structures.
Frequently Asked Questions
Does Downey allow tiny houses as a legal dwelling type?
What building code applies instead of the standard house rules for a Downey tiny house?
Do Downey's seismic and structural amendments still apply to a tiny house?
Sources & Official References
Other rules in Downey
California rules heatmap·Compare Downey to another location·View the California accessory structures overview
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