Downey, CA Fence Regulations: Retaining Walls (2026)
Key Facts
- Permit-exempt height
- 4 feet, footing bottom to wall top
- Exemption lost if
- wall supports a surcharge or liquids
- Governing section
- Downey Municipal Code § 8999.28(b)(1)(iv)
- Wood restriction
- banned in Seismic Design Category D, E, F
- Enforcement
- Building Official; stop work order § 8999.46
- Unpermitted work penalty
- investigation fee equal to permit fee
Summary
Downey exempts retaining walls up to four feet tall, measured from the bottom of the footing to the top of the wall, from a building permit under the city's Administrative Building and Housing Code. Taller walls, and any wall supporting a surcharge or impounding Class I, II or IIIA liquids regardless of height, need a permit and Building Official review before construction starts.
(a) Required. Any owner or authorized agent who intends to construct, enlarge, alter, repair, move, demolish, or change the occupancy of a building or structure, or to erect, install, enlarge, alter, repair, remove, convert or replace any electrical, gas, mechanical or plumbing system, the installation of which is regulated by the codes, or to cause any such work to be done, shall first make application to the Building Official and obtain the required permit. (b) Work Exempt from Permit. ... Permits shall not be required for the following: (1) Building: ... (iv) Retaining walls that are not over four feet (4′) (1,219 mm) in height measured from the bottom of the footing to the top of the wall, unless supporting a surcharge or impounding Class I, II or IIIA liquids.
Official source re-checked September 7, 2026: no newer edition of the code had been published (publisher’s edition: rev 4807734; v5 updated 2026-01-27).
Full Breakdown
28(a) requires any owner or authorized agent who intends to construct, enlarge, alter, repair, move, demolish or change a building or structure to first apply to the Building Official and obtain a permit. " A backyard retaining wall at or under four feet, holding back ordinary soil with no surcharge load, can go up without a building permit, though the code makes clear that exemption "shall not be deemed to grant authorization for any work to be done in any manner in violation" of other code provisions.
Any retaining wall over four feet, or one of any height that supports a surcharge such as a driveway, parking area or structure above it, or that impounds Class I, II or IIIA liquids, needs a permit and engineered plans reviewed by the Building Official. 2 so that retaining walls assigned to Seismic Design Category D, E or F cannot be built partially or wholly of wood, and Section 8022 requires any wood used in a retaining or crib wall to be preservative-treated under AWPA U1 standards for soil and fresh-water use, again barring wood entirely in Seismic Design Category D, E or F structures.
Where a retaining wall raises the grade next to a city street tree, the code separately requires the wall to be built porous enough to allow root aeration.
Violations & Fines
Building an exempt-height retaining wall does not excuse other code violations, and building one taller than four feet, or one carrying a surcharge, without a permit makes it an "unpermitted structure" under Section 8999.44.5. The Building Official can issue a stop work order under Section 8999.46, and continuing work after a stop-work order, or any unlawful construction under Section 8999.44, is "subject to penalties as prescribed by law," on top of an investigation fee equal to the permit fee under Section 8999.36(d).
Frequently Asked Questions
How tall can my retaining wall be without a Downey building permit?
Can I build a retaining wall out of wood in Downey?
What happens if I build a wall taller than four feet without a permit?
Does the four-foot exemption apply if the wall holds back a driveway above it?
Sources & Official References
Other rules in Downey
California rules heatmap·Compare Downey to another location·View the California fence regulations overview
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